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A Fish

Fish Health Sheet – Important Information to give Before Asking Questions

Diseases can be one of the most frustrating and confusing aspects of fishkeeping, and sometimes you’ll have to ask others for help. To make it easier, it’s best to give as much information as possible so others can help you quickly and efficiently.

The Basics

What's gone wrong, exactly. Symptoms include anything you've noticed about your fish. This could be: External, such as fluffy patches, ulcers, wounds, discolouration, spots, parasites, eye problems, or even what their poop looks like. Internal, such as a sunken belly. Behavioural, such as not eating, hiding away, bumping into things, darting and anything out of the ordinary. 

Symptoms


Affected fish (is it a single sick fish, or the whole tank, any deaths) 


How long have you had the affected fish


Recently introduced fish or other livestock (and how long ago was it introduced, were there any sick fish in store)


Recent changes (have you made any changes to the tank, what were they and when were they changed)


Setup

Tank Size


Tank Stocking (the types and amounts of fish and other creatures living in your tank)


Food regime (what foods do you feed and how often)


Filter model (and do you clean it; if so, how thoroughly and how often)


Tank flow (does the water move fast, or does it sit still)


Have you attempted any medications (if so, what type, for how long and was it in the main or quarantine tank)


Parameters

Anything to do with water chemistry and water quality: For this you will need a thermometer and a reliable test kit (liquid test kits preferable as test strips tend to be inaccurate). If you don’t have a test kit, a local pet/fish store should be happy to test your water for free. Water softness can be taken from your local water reports (or may be measured with a test kit).

Temperature


Ammonia


Nitrites


Nitrates


pH


GH/KH (water softness, don’t worry if you don’t know these, but they can be useful)


Humane Fish Euthanasia

Fish euthanasia is certainly not an easy topic to discuss, and it’s one we all avoid until the time comes. This usually leaves us in a state of panic and confusion as there are so many differing opinions out there on the internet, and it’s even more confusing when we have a sick fish that needs to be euthanized. The topic of euthanasia, as you likely know, is a controversial one. Here I aim to provide some information on what methods are currently considered most humane, and what methods should be avoided. Unfortunately the most humane methods appear to us to be brutal, and this can be very stressful on any fish owner – it’s important to understand the reasons behind these methods and why they’re preferred.

 

Reasons for Euthanasia

This is the first important thing to consider. Some people prefer to let “Nature take its course”, others feel that when a fish has poor quality of life euthanasia is the best option. Sometimes euthanasia is necessary when, for example, a fish is infected with something like a virus and it’s important to ensure that no other fish pick away at it when it dies to avoid spreading the virus (and quarantine tanks is impractical for the situation). Other times people may feel human intervention is not necessary and to allow the fish to live out the rest of its life. Euthanasia is typically considered a last resort for a sick fish, so you want to make sure of two things.

  1. The fish isn’t likely to be cured. This can include disease, such as Columnaris or dropsy (often bacterial infections), where typically it is “too late” for the fish by the time the disease is noticed. Diseases such as Neon Tetra Disease or Tuberculosis are incurable and Euthanasia is considered necessary to reduce suffering and to avoid the spread of the disease. Often the fish is at a state of sickness where any medications required for the disease are likely to kill the fish through stress, and the disease has simply become too severe for the fish to recover. This can also include damage such as internal damage to the fish, where the swim bladder, brain or other organs are affected and the fish can no longer function and will likely waste away due to side effects of the damage.
  2. The fish has poor quality of life. This is the most important thing to consider when euthanizing any animal. It can be hard to judge what determines good “quality of life” for a fish, and it is up to the individual to decide. Some signs that could determine a poor quality of life* could include gasping at the surface, swimming upside down, unable to swim, unable to eat, lethargy (eg sitting at the bottom of the tank) and what looks to be signs of pain (especially if there is external infection) - but most of all trust your instincts.

*Note: these can also be symptoms of disease and water quality issues, so make sure it’s not something with a solution)

 

Methods to Avoid

It is essential to avoid these methods to reduce stress on both you and the fish. Some methods speak for themselves, but others are still commonly suggested despite them not being suitable forms of euthanasia. Some are based on “out of sight, out of mind” however even though they are out of sight, the fish is left suffering.

  • Flushing. This is possibly the worst method. It is not an instant death and unfortunately leaves the fish going through sewage, slowly dying due to the sickening water conditions. It is also not recommended to dispose of dead fish through flushing as it can allow for accidents or diseases getting into waterways.
  • Freezing or Boiling. These are both slow methods and are both incredibly painful and stressful for the fish. Putting a fish into ice water is sometimes recommended to shock a fish before euthanasia – this has to be done “just right” or else it could end up putting the fish through a lot of pain and stress. FishChannel recommends to only use shocking in ice water on fish under 2 inches.
  • Fish out of Water. This is a bit like trying to down a mammal – it’s also very slow and very scary! Some fish can last out of water for a long time.
  • Vodka or other Alcohol overdose. The fish is well aware of what is in their water – this is very stressful and also not a quick method, and likely quite painful. Vodka may be used after a fish is anaesthetized but can certainly not be used on a conscious fish.

 

Suitable Methods

This is, unfortunately, the hard part. Quick and fast death is recommended by many fishkeepers, but it can be difficult for some. This is totally understandable, but it is recommended to reduce the amount of stress on the fish and to ensure a quick death. The other option is clove oil, however this is less recommended than “brute force” as it can be stressful for the fish and as it is slowly anaesthetized. The following may be difficult to face, but it is considered for the best. This is such a big subject and there are many disagreements, so the information below (like many subjects in fishkeeping) may change over time as more study is done on preferred methods.

 

Quick Methods

There are a few drawbacks to these methods, listed below:

  • The stress of being put into a bag. Obviously being whacked against a wall can be rather stressful, the justification is that this is for a very short amount of time.
  • It can be very difficult for some fishkeepers to go through with these methods.
  • Specific methods involving aim of things such as hammers and pins can be inaccurate and there is a chance of missing, so it is important that the owner is very careful in how they do this.
  • Some methods may involve taking the fish out of water, reducing accuracy and is stressful to the fish.
  • Small fish can be difficult with methods such as the pin to the head, so some methods are recommended predominantly for bigger fish.
  • Pin to the Head. This is only recommended if you have experience with this on eg game fish. It is also recommended mostly on larger fish, as smaller fish can be difficult to deal with. Typically it is recommended that the fish is anaesthetized first before attempting this.
  • Blunt Force Trauma. This, for example, may include putting the fish in a bag and hitting it against a wall, or running it over. You can also use a hammer, or more recommended, a brick to the head. This feels brutal but is a good way to ensure quick death. It is recommended you prepare the “site” that you intend to do this on first to reduce the amount of time the fish is in the bag to reduce stress.

 

Clove Oil

It’s really important to consider the issues with this method before using it. I personally only recommend clove oil if “brute force” methods are not suitable in cases such as the owner being too uncomfortable with them, or if for example the fish needs to be preserved for something like dissection/necropsy/tissue samples. Clove oil can take a long time and many feel that it is stressful on the fish. The concerns are these:

  • The process of moving and keeping the fish in a different container for ~30 minutes can be stressful for the fish.
  • The addition of a foreign chemical into their water can be stressful, remembering that fish are well aware of what is in their water. It is good to note, however, that PracticalFishkeeping has noted that Clove oil was found to be less “noticed” by fish in comparison to other anaesthetics.
  • The amount of time it takes for the process is considered quite lengthy
  • Fish seem to become stressed when going through the process of being anaesthetized, as they are aware they are losing the ability to swim and stay upright, which for a fish is a pretty important goal.
  • If done wrongly it can cause a lot of stress to the fish as it is confused with what is going on.
  • It can be a bit too stressful on big fish, so it is recommended predominantly for small fish.

 

Nevertheless, clove oil can be considered the preferred method for some. Opinions on how to perform this method vary, and I will mention the two different practices. Clove oil is a very distinct smell and due to its properties as an anaesthetic it’s best to use disposable containers not intended for future use (eg for use of holding foods). It’s also recommended to wear gloves and to not inhale it too much – you may end up feeling rather sleepy!

 

Clove oil is sometimes used for toothaches in humans and is readily available at your local pharmacy. It comes in a small bottle, but will last you a long time (hopefully you don’t have to use it often). You will need bottle such as a plastic drinking bottle with a lid, a container and some clove oil.

  1. Fill the drinking bottle with a bit of aquarium water (about 10cm of water) and use a single drop of clove oil. This doesn’t seem like much but it’s very strong. Close the bottle and shake it until the water goes milky – if you don’t shake it enough, the oil simply gathers at the top of the water.
  2. Transfer the fish into a small container (with the water from the aquarium), an ice cream container works (obviously a larger container if the fish is too large for an ice cream container), with about 5cm of water above the fish. A dark container can be best to reduce the amount of stress on the fish.

 

The next bit becomes a bit tricky as advice varies. Some feel this process must be done as slowly as possible – others prefer to do it quicker (but not dumping all the clove water in there) as to reduce the amount of time it takes.

  1. Typically recommended is to add drops of the clove water over a period of 5-20 minutes. The fish may be confused at first but by doing it slowly the fish isn’t freaked out by a sudden influx of a foreign chemical into its water. It will slowly fall asleep. Others prefer to put about ¼ of the clove water in and then continue after it has fallen asleep.
  2. The fish at this point is asleep but hasn’t passed – there may be gill movement but he won’t react to stimuli (eg being touched). You then have multiple options of euthanasia including, for example, freezing or adding much more clove oil to successfully overdose as the fish is anaesthetized and cannot feel anything. Around 400mg/L is required to successfully overdose a fish according to the RSPCA
  3. After 10 minutes of no gill movement, the fish is considered dead and may be disposed of however you choose. It is absolutely recommended to not dispose of the fish in any waterways for example by flushing.

 

Anaesthetic

The final option, anaesthetics, may only be administered by a vet. This may be impractical for many but may be useful for a fish which, for example, is ill and needs samples taken by the vet to identify the affecting disease. I would recommend consulting your preferred vet on what they offer in euthanasia techniques.

Euthanasia techniques can be a very personal decision but when followed correctly the above recommended techniques should hopefully provide quick and humane death. If you are unsure about what technique to use, it may be worth consulting your preferred vet on what their feelings are on the matter. As said above, this is a very controversial topic. I do not aim to give any specific opinions but the correct information for you to personally decide what is best for you and your fishy friend. I hope this article is of some help for what is a very stressful time for any fishkeeper.

If you have any comments on the article please leave a comment below, or let us know via the Contact Us link in the main menu.

Water Parameters

What to mention when asking for help to diagnose fish diseases

 

Forums can gather several posts a day with the same panicked question, "What's wrong with my fish?", and this is a question we all have to ask on occasion when dealing with disease. Fish diseases can show in many different ways and it's not uncommon for a group of us hobbyists to become stuck when trying to diagnose an illness. Knowing your water parameters can really speed up the process and water quality can even be the direct cause of the fish's illness.

One major step is ruling out the basics. It can be dangerous to assume that water conditions are pristine and to medicate for what may appear to be a disease, because more often than not the symptoms may be caused by what's going on in the water rather than a specific disease affecting the fish. This is why you may hear the question repeated like a broken record, "What are your water parameters?"

I know, this all can seem both boring and complex, but it really is important to working towards helping your fish get better.

 

 

What are your Water Parameters?

This can refer to several different levels of certain compounds in the tank. Water parameters usually refers to:

  • Ammonia
  • Nitrite
  • Nitrates

If you don't know what these are, this article may be of some help. These above compounds are essential to understand and measure when a fish is sick.

It can also mean the pH. Often this isn't actually an issue, even though it's usually what everyone tests. An unstable/fluctuating pH is typically more dangerous for fish than the pH reading itself. The majority of fish in aquariums have been captive bred for many generations, and while it is certainly preferable to maintain their optimal pH, these fish tend to be hardy and disease may not be directly caused by a pH slightly out of the optimal range.

GH and KH can also be useful, but are often not necessary. If you have a GH or KH test kit, it can be useful to know these "just in case".

 

Why do you need to know these?

As mentioned above, it can be dangerous to medicate fish straight away, as many medications are stressful on fish and can have several indirect consequences (such as overuse of Antibiotics). These above parameters can have very strong effects on fish and can cause several common symptoms. Ammonia, for example, is highly toxic and burns the gills of fish and can cause permanent damage. Nitrite is also considered just as toxic. Nitrates tend to be less toxic, but can become dangerous above levels of 20ppm for sensitive fish and 40ppm for hardy fish.

 

But my Parameters are Fine?

Unfortunately, fine doesn't tell us much. It's not uncommon for someone to tell you that the parameters are fine, however numbers can be needed as what is fine for one fish may not be for another. These parameters truly are essential for diagnosing fish (I cannot emphasize this enough!) and while they may look to be in small amounts, they can have huge effects on the health of your fish. 0.25ppm can look like a small number, but for a fish it's a lot (imagine if you were breathing in even small amounts of Ammonia all day?). Another example is Nitrates, which may range between 5-40ppm in the aquarium - these may be the recommended ranges for your tank, but when you learn that in the wild Nitrates rarely go above 6ppm in healthy waterways, you realize how polluted our tanks already are when considered clean!

 

I Regularly do Water Changes?

Even the experts can experience an Ammonia spike - while water changes are essential for maintaining your Nitrate levels, the unexpected can occur and this can cause a sudden onset of symptoms in your fish. Simple problems such as an unnoticed rotting plant or dead fish can cause a sudden spike in any one of the parameters. Filters can become blocked without being noticed and this too can cause an issue. In very rare cases, your tap water can become contaminated and without knowing you can accidentally be poisoning your fish!

 

What if I don't have a Test Kit?

Many of us didn't buy the test kit until we needed it, and unfortunately it's usually a lesson everyone learns the hard way. It can seem silly to spend $60 on test kits until the time comes and you find a fish getting sick caused by water conditions. If you don't currently have a test kit, there's no need to worry! Your local fish store will often test your water for free and test kits can regularly be found on sale. If you only have a single small tank it may be reasonable to rely on your LFS for testing, however when you have larger and multiple tanks it can become an emergency when the fish store is closed late at night or on a holiday and you need instant testing. Because of this, I recommend a master test kit as an essential item for the vast majority of fishkeepers.

 

So how may these Parameters Affect my Fish?

Poor water quality increases stress in fish and decreases their immune system, making them susceptible to disease. This is an indirect effect, but these symptoms below may be a direct effect of poor water conditions:

  • Gasping (either at the top of the tank, or the bottom of the tank)
  • Lethargy (eg sitting at the bottom of the tank)
  • Burned gills, red streaks in fins, red wounds on scales
  • Swim bladder symptoms: Spinning around, lying on the side, swimming upside down
  • Death, mass deaths

These are all some of the most common symptoms I see in sick fish, indicating how often water parameters can be the cause of fish deaths.

 

So what Should I do when I have a Sick Fish?

These are my (personal) "order of operations" when I find a fish is sick:

  1. Take photos, test water parameters.
  2. Do a water change! 99% of the time this benefits any sick fish, and is almost always a recommended step. If you don't have a test kit, it's preferable to keep some of the older water in a jar so that it can be tested later.
  3. Ask on forums. I tend to prefer asking on local forums as illness outbreaks may be noticed locally and may help you figure out what disease your fish has. Some diseases are less common in New Zealand due to our quarantine procedures, which allows us to typically rule out certain causes.
  4. Some fish may need to be isolated (or, unfortunately, culled) depending on the disease. Some diseases such as Ich live in the water and isolation is ineffective, others such as Viruses and Bacterial infections are highly contagious and isolation of sick fish may be preferred. Some fish may need to be isolated if their environment is too stressful, eg if others are nipping at it.
  5. Finally, if your water parameter tests come back healthy and the disease can be "roughly" (eg Parasitic, Fungal or Bacterial) or accurately diagnosed (Eg Columnaris sp, Saprolegnia, Ich) a medication can then be administered. Medication should be your last action, not your first!

 

Is There any Other Information that Might be Useful?

Certainly! When diagnosing, it's best to give as much information as possible. Here you can find a list of answers to fill out which are ideal for people to know when helping to diagnose your fish. Extra information is greatly appreciated and really helps to speed up the diagnosis process. One thing to note are all symptoms the fish is experiencing such as External symptoms (eg patches, sores, fin rot), Internal symptoms (eg sunken belly, bloat) and Behavioural symptoms (eg gasping, erratic behaviour, lethargy).

Another is how many fish are affected in the tank? Certain diseases may only affect one fish, some may affect many all fish, others may only affect one species. This also allows us to determine whether it's spreading or an isolated incident. Basically, anything out of the ordinary is important to know!

 

Have any other questions? Feel free to let us know in the comments below or send a question through Contact Us!

Medications in NZ

This is the real information you've been waiting for! Whilst this is likely the more relevant article to many, we really do recommend the Part One for developing an understanding on When to medicate, Why to medicate and What to medicate with.

Index of Medications:

Intro

In New Zealand, we are restricted on what kinds of medications we can access and use for the purpose of treating animals. All of our medications in the country are registered as ACVM (Agricultural Compounds & Veterinary Medicines) products, which is a pricey and lengthy process. Due to this registration process, it is not legal to bring in medications from overseas intended for use on animals without Special Circumstances approval, and restricted medications require a veterinary prescription. The following are all medications registered to specific companies, or are available from your local veterinarian with a prescription.

We are not vets and the following pieces of information are simply guidelines to help figure out the steps in treating your fish. As information in the hobby changes frequently, we will try to keep this article up to date, however not all advice may be completely accurate and we strongly recommend you do further research on the topic. Always seek professional Veterinary advice before medicating animals.

Please Note! mg/L is different to mL/L. mg/L is given in case your medication at home is in a powdered form or is in a different concentration solution. To convert: 2mg/L = 2mL of a 1% solution per 10 Litres, or 0.2mL of a 1% solution per Litre. 2mL per Litre of a 1% solution is 1mL per Litre of a 2% solution, 0.7mL per Litre of a 3% solution and 0.4mL per Litre of a 5% solution.

Make sure to remove Carbon when treating with any medication.

These are our definitions of Short-Term, Medium-Term and Long-Term Baths (click the image for a larger size):

Long Short Term Baths Medication

 

Medications:

Acriflavine (External Parasitic and Fungal Infections, Antiseptic against External Bacterial infections

Acriflavine 01

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (at commonly found concentration):
Recommended Dosage (mg/L):
External Parasitic Infections, Mild Fungal Infections, Topical Application is sometimes used on wounds to help prevent bacterial infection.
Liquid
Local Pet Store
5%
Yes, but typically only recommended to be applied topically.
Long Term or Short Term Bath, Topical Application.
Yes, but is unlikely.
Yes, will kill plants.
Yes.
No.
Discolours water and may stain decorations/silicone, believed to cause infertility in fish. Is a dye, so gloves are recommended for handling.
0.02-0.06mL/L for Prophylactic Measures or Minor Infections. Up to 0.2mL/L as a Long-Term Bath for Severe Infections, however this may be too stressful for many fish.
0.1-0.3mg/L for Prophylactic Measures or Minor Infections. Up to 2mg/L as a Long-Term Bath for Severe Infections, however this may be too stressful for many fish.

 

 

Epsom Salts (MgSO4 - Internal Parasitic Infections, Bloat)

MgSO4 01

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (g/L):
Bloat/Constipation, Mild Internal Parasitic Infections.
Salt Crystals
At local Supermarkets, Pharmacies or Health Stores.
N/A
Yes, but not often used.
Long Term, Medium Term or Short Term Bath.
Unlikely.
Unlikely.
Yes.
Yes.
Generally safe to use, however discontinue if signs of stress start to show. An Anthelmintic (eg Praziquantel) is typically recommended instead for Internal Parasitic Infections, however Epsom Salts may be used as a supplementary medication. Make sure to dissolve the crystals before adding them to the tank. Short-Medium Term Baths are usually recommended over Long-Term Baths.
From 3.5-10g/L for a Short-Term Bath, 0.3-0.8g/L for a Medium-Term Bath and 0.003-0.005g/L for a Long-Term Bath.

 

 

Formalin (External Parasitic Infections)

Formalin 01 01

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (at commonly found concentration):
Recommended Dosage (mg/L):
External Parasitic Infections (such as Ich, Velvet or some Gill Parasites).
Liquid
Local Pet Store
5%
Not recommended.
Long Term or Short Term Bath.
Yes.
Yes, will kill plants.
Yes, although use lower doses or discontinue use altogether if signs of stress show.
Not likely.
Toxic and Carcinogenic, be sure to not inhale the fumes and always wear gloves when handling. Store in a dark place over 4°C and use fresh - do not use when a white precipitate forms. Toxicity increases in soft water, and this medication will also reduce Oxygen levels in the tank - provide increased aeration when using. Do not use in conjunction with Praziquantel.
0.9-3.0mL/L for a Short-Term Bath, or 0.075-0.15mL/L for a Long-Term Bath
9-30mg/L for a Short-Term Bath, or 0.75-1.5mg/L for a Long-Term Bath

 

 

Levamisole (Internal Parasites - Callamanus Worms/Nematodes)

Levamisole 01

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (at commonly found concentration):
Recommended Dosage (mg/L):
Internal Parasitic Infections - considered the best medication for Callamanus Nematode Infections
Liquid
Veterinarians as a wormer for Birds, and certain Local Pet Stores.
10%
Yes.
Long Term Bath or, ideally, via Food.
Unlikely.
Unlikely.
Yes
Typically, yes, however not necessarily with sensitive invertebrate species.
Generally a very safe medication, however discontinue use if signs of stress start to show. Dose can be repeated once every 3 days, with 25% water changes in between. It is typically recommended to treat for at least 3-4 weeks for Callamanus infections. Is a red liquid, so may stain clothing.
0.02-0.025mL/L for a Long-Term Bath.
2-2.5mg/L for a Long-Term Bath. 2mg/g of fish food for 5-7 days.

 

 

Malachite Green (External Parasitic and Fungal Infections)

Malachite Green 01

Spectrum of Use:
Form(s) Available in:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (at commonly found concentration):
Recommended Dosage (mg/L):
External Parasitic Infections (such as Ich and Velvet) and Very Mild Fungal Infections.
Liquid
No longer readily found in New Zealand, but used to be available at a 2% solution.
Not typically, but can be.
Long Term or Short Term Bath.
Yes.
Yes, will kill plants.
Half Dose recommended.
No.
Discolours water, Carcinogenic, make sure to handle with gloves. Easily deactivated by light and organic matter, so it is best to siphon out excess waste and keep lights off during treatment. Toxicity increases in soft water.
0.05-0.15mL/L for a Short-Term Bath, however higher doses are increasingly toxic to many fish. 0.005-0.015mL/L for a Long-Term Bath, however lower doses are recommended for most fish. Repeat half the recommended dose once every 3 days for a maximum of 3 total treatments for Long-Term Baths.
1-3mg/L for a Short-Term Bath, however higher doses are increasingly toxic to many fish. 0.1-0.25mg/L for a Long-Term Bath, however lower doses are recommended for most fish. Repeat half the recommended dose once every 3 days for a maximum of 3 total treatments for Long-Term Baths.

 

 

Methylene Blue (External Parasitic and Fungal Infections, Prophylactic)

Meth Blue 01

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (at commonly found concentration):
Recommended Dosage (mg/L):
External Parasitic Infections (eg Ich and Velvet), Fungal Infections and as a Prophylactic Measure. Topical Application may be useful for Minor Infections or on Wounds. Sometimes used to prevent Fungusing on fish eggs.
Liquid
Local Pet Store
1%
Yes.
Long Term or Short Term Bath, Topical Application.
Yes, but is unlikely to do so at lower doses.
Yes, will kill plants.
Typically, although a Half-Dose may be desirable.
No.
Discolours water blue and will stain decorations/silicone, is a dye so gloves are recommended for handling.
0.1-0.35mL/L for Prophylactic Measures or Minor Infections and as a Long-Term Bath. Up to 20ml/L for a Short-Term Bath, however many fish will not handle such a high dose.
1-3.5mg/L for Prophylactic Measures or Minor Infections and as a Long-Term Bath. Up to 200mg/L for a Short-Term Bath, however many fish will not handle such a high dose.

 

 

Praziquantel (Internal Parasites and Flukes)

Prazi 01

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (at commonly found concentration):
Recommended Dosage (mg/L):
Internal Parasitic Infections, Gill Flukes.
Liquid, Tablet or Powder
Local Veterinary Practice (as Pure 50mg Tablets), certain Local Pet Stores.
3-4%
Yes.
Long-Term Bath or in Food. Dosing food is typically recommended, as this is a more effective way to target internal parasites (Praziquantel also has poor solubility).
Unlikely.
Unlikely.
Yes.
Typically Safe.
Generally a very safe medication, however discontinue use if signs of stress start to show. Dose can be repeated once every 3 days, with 25% water changes in between. It is typically recommended to treat for 3-4 weeks for general Internal Parasitic Infections. Due to its poor solubility, make sure to the liquid vigorously to mix. For Callamanus Nematodes, Levamisole is the preferred medication (however both may be used in conjunction with each other). Do not use in conjunction with Formalin.
0.06-0.09mL/L for a Long-Term Bath.
2.0-2.5mg/L for a Long-Term Bath, or as 2-2.5mg/g of Food. For Long-Term Baths, crush the tablet and add to some warm water. Shake vigorously, and then add to the tank.

 

 

Potassium Permanganate (External Parasitic Infections)

KMNO4 01

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (mg/L):
Severe External Parasitic Infections
Crystals
Local Garden Store, Local Pharmacy
N/A
No.
Short Term Baths
Yes.
Yes, will kill plants.
No.
No.
Potassium Permanganate is a very strong oxidiser and is highly toxic to many life forms. It is only recommended as a last resort or in emergencies, and great care must be taken. Will stain hands, clothing and equipment, so gloves are recommended. Deactivates in light and with organic matter, so storing in a dark place is necessary. It is not recommended to dose a display tank. Make sure to dissolve the crystals in water before adding.
10-20mg/L for a Short-Term Bath of 30-120 Seconds.

 

 

Salt (NaCl - External Fungal, Bacterial and Parasitic Infections, Prophylactic)

NaCl 01

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (g/L):
External Parasitic Infections, Mild Fungal Infections, as a Prophylactic Measure against External Bacterial Infections. We recommend Topical Application against External Infections when possible, rather than Baths. May be used with very mild External Bacterial Infections such as the beginnings of Fin Rot.
Salt Crystals
Local Pet Store, local Supermarket. There is debate around whether Iodized Salt is acceptable to use, however it is typically recommended to use Non-Iodized Salt free of any Anti-Caking Agents.
N/A
Yes, but typically only recommended to be applied topically. Its use as a Prophylactic Medication in Long-Term Baths is argued, however we feel that it is typically not necessary.
Long Term or Short Term Bath, Topical Application.
Yes, but is unlikely unless in high concentrations.
Yes, will kill plants in high concentrations.
Half-Dose recommended.
Typically not.
More toxic to soft-water fish, other medications such as Malachite Green and Formalin may be recommended for effective use against parasites. Reduces Oxygen levels in the water, so increased aeration is recommended. Make sure to dissolve crystals in water before adding.
0.08-5g/L for a Long-Term Bath, with lower doses preferred for soft-water and sensitive fish. 10-30g/L as a Short-Term Bath for 5-30 Minutes, however it is recommended to discontinue the Bath if fish begin to show signs of stress.

 

 

Antibiotics (Bacterial Infections)

As mentioned in our previous article, we do not recommend the use of Antibiotics unless the disease is diagnosed, and other options are not suitable. This is due to the impact over-use of Antibiotics can have on our Fish, Us and our Environment.

 

Nitrofurazone

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (at commonly found concentration):
Recommended Dosage (mg/L):
External and Internal Bacterial Infections, is a Broad-Spectrum Antibiotic which targets both Aerobic and Anaerobic Bacteria, however Metronidazole is often recommended instead for Internal (typically Anaerobic) infections.
Powder
No longer available Over-The-Counter, but used to be available as Furan-2. Is now only available with a Veterinarian Prescription (in which other Antibiotics may be recommended instead).
 
No.
Short-Term and Long-Term Bath (full recommended course is required)
It may, but is claimed not to.
Yes, will kill plants.
Yes.
No.
Discolours water, is considered a Carcinogen, and is no longer readily available. Always wear gloves when handling as it is prone to causing reactions with the skin. Some feel that common Bacterial Infections such as Columnaris in New Zealand are resistant to Furan-2 due to our heavy use when it was available.
For Furan 2: One packet per 38L, dosed for 4 Days total. Perform a 25% water change before dosing, on Day #2 and Day #4.
100mg/L for 30 Minutes, every day for 3 days as a Short-Term Bath. 2.5-5mg/L for 2-3 Days as a Long-Term Bath.

 

 

Furazolidone

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (at commonly found concentration):
Recommended Dosage (mg/L):
Similar to Nitrofurazone, and is another component in Furan-2.
Powder
No longer available Over-The-Counter, but used to be available as Furan-2. Is now only available with a Veterinarian Prescription (in which other Antibiotics may be recommended instead).
 
No.
In Feed and Long-Term Bath (full recommended course is required)
It may, but is claimed not to.
Yes, will kill plants.
Yes.
No.
Discolours water, is considered a Carcinogen, and is no longer readily available. Always wear gloves when handling as it is prone to causing reactions with the skin. Some feel that common Bacterial Infections such as Columnaris in New Zealand are resistant to Furan-2 due to our heavy use when it was available.
For Furan 2: One packet per 38L, dosed for 4 Days total. Perform a 25% water change before dosing, on Day #2 and Day #4.
5-10mg/L for 2 Days. 3mg/g of Food, Twice-Daily for 6 Days total.

 

 

Metronidazole

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (at commonly found concentration):
Recommended Dosage (mg/L):
Internal Bacterial and Parasitic Infections, Hexamita Parasites (Hole in the Head Disease). We do not recommend the use of this medication on Internal Parasitic Infections unless Praziquantel or Flubendazole has been attempted first, and we do not recommend the use of this medication on Internal Bacterial Infections or Hexamita Parasites until Food Quality, Food Type and Water Parameters (Ammonia, Nitrites and Nitrates) have been corrected.
Powder/Tablets
Is only available with a Veterinary Prescription.
 
No.
In Feed, in Short-Term and Long-Term Baths (full recommended course is required)
As most Filter Bacteria is Aerobic (for Nitrification), it should not affect these. However, Anaerobic Bacteria (for Denitrification) may be affected, and checking water parameters regularly is recommended.
Possibly.
Yes.
No.
Is not particularly soluble, so treatment in Feed is recommended over Baths.
N/A
5-7.5mg/L for 2-3 Days. 5mg/g of Food Twice-Daily for 6 Days Total.

 

 

Other Medications and Combinations

The following medications may not be readily available, may not be commonly used, or may require combining different kinds of medications.

 

Flubendazole

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (at commonly found concentration):
Recommended Dosage (mg/L):
External Parasitic Infections and Skin & Gill Flukes
Powder/Tablets
May be available as a Dewormer for other animals, or with a Veterinary Prescription. Was previously available as Kusuri Wormer
50mg/g Flubendazole for Kusuri Wormer Plus
Yes.
In Feed, in Short-Term and Long-Term Baths (full recommended course is required)
Unlikely
Unlikely.
Yes.
No, although it may be safe with "hardy" Invertebrates.
Is not particularly soluble, so treatment in Feed is recommended over Baths.
2.6mg/L, with a second dose after 4 Days if required.
1-2mg/L for 2 Days, and may be repeated after a week for a total of 2 treatments. 1mg/g of Food every 2nd Day for 10 Days Total.

 

 

"FMC" Formalin + Malachite Green

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (at commonly found concentration):
Recommended Dosage (mg/L):
External Parasitic Infections, External Fungal Infections.
Liquid
Formalin can be found at a local Pet Store, however Malachite Green is no longer readily available.
5% Formalin Solution, 2% Malachite Green Solution.
Not Recommended.
In Short-Term and Long-Term Baths.
Yes.
Yes, will kill plants.
Not always - Half Dose recommended.
No.
Formalin: Toxic and Carcinogenic, be sure to not inhale the fumes and always wear gloves when handling. Store in a dark place over 4°C and use fresh - do not use when a white precipitate forms. Toxicity increases in soft water, and this medication will also reduce Oxygen levels in the tank - provide increased aeration when using. Do not use in conjunction with Praziquantel. Malachite Green: Discolours water, Carcinogenic, make sure to handle with gloves. Easily deactivated by light and organic matter, so it is best to siphon out excess waste and keep lights off during treatment. Toxicity increases in soft water.
Mix 5mL of Malachite Green with 50mL of Formalin and dose 0.025mL/L 2-3 times total for 7-14 Days
Mix for a ratio of 0.1mg/L of Malachite Green to 25mg/L of Formalin.

 

 

Melafix by API

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (at commonly found concentration):
Supplementary/Prophylactic Medication against External Bacterial Infections.
Liquid
At any local Pet Store or Fish Specialist.
1% Cajeput Oil
Yes
Long-Term Baths.
Unlikely.
Unlikely.
Yes.
Yes.
There are many different opinions around how effective this medication is, and whether it should only be used as a Prophylactic Measure. It is in the opinion of this author that this medication is best used as a Prophylactic Measure, and that Antibiotics are likely to be needed for more severe Bacterial Infections. There is also concern around the use of this medication with Labyrinth Organ fishes (Those in the suborder Anabantoidei) and its affect on both their Labyrinth Organ and their ability to take up air through the oily surface created.
0.13mL per Litre or 1.3mL per 10 Litres. Shake well before use, and dose Daily for 7 days. Make a 25% Water Change on Day 7, and continue use if necessary.

 

 

Pimafix by API

Spectrum of Use:
Form(s) Available in:
Where Found:
Concentration Commonly Found in NZ:
Can be Used as a Prophylactic Measure?
Typical Application:
May Affect Filter Bacteria?
May Affect Plants?
Safe With Scaleless Fish?
Safe With Invertebrates?
Other Notes:
Recommended Dosage (at commonly found concentration):
Supplementary/Prophylactic Medication against External Fungal and Bacterial Infections.
Liquid
At any local Pet Store or Fish Specialist.
1% Bay Oil
Yes
Long-Term Baths.
Unlikely.
Unlikely.
Yes.
Yes.
Like Melafix, there are many different opinions around how effective this medication is, and whether it should only be used as a Prophylactic Measure. It is in the opinion of this author that this medication is best used as a Prophylactic Measure, and that Antibiotics are likely to be needed for more severe Bacterial Infections. There is also concern around the use of this medication with Labyrinth Organ fishes (Those in the suborder Anabantoidei) and its affect on both their Labyrinth Organ and their ability to take up air through the oily surface created.
0.13mL per Litre or 1.3mL per 10 Litres. Shake well before use, and dose Daily for 7 days. Make a 25% Water Change on Day 7, and continue use if necessary.

 

Medications Part One

Due to the length of this topic, we have split it into two different articles. This is Part 1: Understanding what "type" of medication to use, when to use medication and when to quarantine fish. Part 2 can be found here!

 

Intro

Choosing what medications to use can be a scary job, especially in New Zealand where we are restricted on what we can use. Choosing the right medication for the situation is essential for treating fish, as many have adverse affects on fish and can make a disease worse when incorrectly dosed. With this article, we're hoping to clear up some confusions on dosing medications and help you choose the right medication for your fish.

We are not vets and the following information are simply guidelines to help figure out the steps in treating your fish. As information in the hobby changes frequently, we will try to keep this article up to date, however not all advice may be completely accurate and we strongly recommend you do further research on the topic. Always seek professional Veterinary advice before medicating animals.

 

Medications Banner 01

What To Use:

This will be covered a bit more thoroughly in each individual medication, however choosing what to use is the first step in treating fish. There are five main reasons that a fish may need treating:

  • Treating Wounds (this is often not needed, however some may choose to treat wounds to prevent disease from forming).
  • Other Prophylactic Measures (such as treating a pollutant spike, or preparing for shipping fish over long journeys).
  • Bacterial Infections.
  • Fungal Infections.
  • Internal and External Parasitic Infections

Some of these will need very different types of medication, and some medications needed will be harsher than others. For example, a Bacterial infection may require Nitrofurazone (an Antibiotic, which cannot be used for other infections and can be harsh on both fish and filtration), a Fungal infection may require Methylene Blue (a dye, which is relatively safe but will stain silicone and decoration, and may kill plants), and an Internal Parasitic infection may require Praziquantel (a very safe medication, which can be used periodically to deworm fish). Whilst most fungal infections can be treated similarly, Internal and External Parasites often need different forms of treatment. Bacterial infections often require Antibiotics, however the type of antibiotic will be different based on the type of Bacterial infection.

Detoxifiers/neutralizers such as Seachem's Prime are often used against pollutants, prophylactic measures such as Methylene Blue are still commonly used for shipping such as when fish are exported from overseas.

Viruses, tumours and other lumps & bumps also sometimes occur in the hobby, especially on certain species of fish. However, viruses are not considered treatable as such, and it's often recommended to simply provide the fish with a stress-free environment to live out its life. Not all lumps will grow quickly, and only viruses may need isolation, so fish can live a long life even with these infections.

The following chart may be useful in considering which medications to use, and how to use them:

 

Which Medication

 

When to Use:

As mentioned above, not all infections are treatable, and in some cases it may not be necessary to do anything at all.

For Wounds:

It is not typically necessary to medicate wounds, provided clean water and a stress-free environment is available for the fish to heal in. Isolation is also not typically required, however in tanks with aggressive fish it may be desirable to help prevent further wounds. On severe wounds, or on fish prone to infections (or fish with existing infections), one may choose to apply prophylactic medications to prevent infection.

Common prophylactic medications may include Salt (NaCl) or Methylene Blue, applied either as a long term bath, short term bath or applied topically.

 

For Other Prophylactic Measures:

You may notice Methylene Blue (which leaves a strong blue tint to the tank's water) being used on quarantined tanks or even sometimes with shipped fish (this is less common with domestic shipping, however an importer may receive fish with Methylene Blue in the water). This is due to the dye's use against Ammonia or Nitrite poisoning by increasing the blood's ability to move oxygen around the body. Methylene Blue is typically tolerated better by fish than other dyes such as Malachite Green, however it is still sometimes recommended to dose half the amount with scaleless and sensitive fish.

Despite this, other safer methods such as using detoxifiers/neutralizers such as Seachem's Prime are now available for detoxifying pollutants, and these would typically be recommended over the use of medications.

Salt is used less commonly as a Prophylactic measure nowadays, however this may still be recommended at small doses with new fish. The opinions on the use of salt differ greatly, and whether you choose to use it is up to you. We recommend reading the Skeptical Aquarist's article on the misuse of salt in the aquarium to help understand the differing perspectives for and against the use of salt as a preventative.

 

For Bacterial Infections:

It is true, not all Bacterial infections require Antibiotics. However, more severe infections are significantly less likely to heal without the aid of Antibiotics. Bacterial infections can be very tricky to treat, as it can be near impossible to correctly diagnose an infection without the use of a microscope and Gram-Positive/Gram-Negative staining techniques. Because of this, it can be difficult to choose the correct antibiotic for treating an infection, and we recommend consulting a local vet who specializes in exotics for obtaining a diagnosis.

Mild Bacterial infections (such as some forms of fin-rot) may respond to the addition of prophylactic medications, but Antibiotics are likely necessary for severe infections. Some infections, such as Columnaris (caused by Flexibacter bacteria) infect and kill fish very quickly, whilst others such as Fish TB (or Fish MB, caused by Mycobacteria strains) are considered to not be treatable at all.

We will cover Antibiotics in a section of its own, as the use of this kind of medication in New Zealand is heavily regulated and is not always practical.

 

For Fungal Infections:

Most noticeable Fungal infections require treatment of some kind, but it is necessary to determine the cause of the infection. Types of Fungi such as Saprolegnia (a fungus which grows white tufts, almost like dandelions) only develop on necrotic cells, and is not necessarily what we are to be treating. Saprolegnia may grow on a Parasitic infection, Bacterial infection or a wound, and the underlying infection is what actually requires treatment.

However, topical application of salt or dyes typically works to kill the fungal infection, and can be used to help determine what the cause is underneath. Funguses can root quite deep underneath the skin, so it is important to not try to pull off or cut out any of the developed growth.

 

For Parasitic Infections:

There are a variety of different treatments for different types of Parasitic infections, and a few key factors need to be determined before treating.

For example, Praziquantel is often used for general Internal Parasitic infections (such as most Internal Parasites causing emaciation, or against Gill Flukes), however Levamisole is necessary for Callamanus worms (which are known for being small red nematodes seen under the fish's anus).

External Parasitic infections typically require dyes and salts, and won't respond to the above two treatments.

Hexamita (Hole in the Head Disease, also known as HiTH) is one Parasitic infection common in Cichlids which is treated completely differently to the rest. Believed to be accelerated by poor water quality and food quality, fixing these two components is the first step to treating the disease. In some cases, the first two do not help, and Metronidazole (a type of Antibiotic) is required for severe infections.

 

To Quarantine or Not to Quarantine?

The following chart may help in figuring out whether isolation/Quarantine is necessary for your fish's disease:

 

To QT

 

 

Antibiotics: When to Make the Leap?

There are several important things to consider when deciding to use Antibiotics. As Antibiotics are regulated heavily here, they are now only available with a prescription from a qualified Veterinarian and need to be used with great care. The New Zealand Veterinary Association (NZVA) has already set a goal to have no Antibiotic use in New Zealand by 2030, and has already met part of that goal by cutting out Antibiotic use in Aquaculture. Because of this, the use of Antibiotics is not something to take lightly, as we are all responsible for the future and well-being of our fish, other animals and ourselves.

Consequences of Antibiotic Overuse:

  • Fish exposed to one type of Antibiotic may not respond well if it is required again for a second infection.
  • Bacterial diseases in the aquatic industry can readily become resistant to Antibiotics, reducing the effectiveness of our main line of defense against them.
  • As our fish require water changes, unfiltered antibiotics enter our drains and waterways, increasing resistance to them for use on both humans and fish.
  • Several types of Antibiotics can affect our filter bacteria, and their use can cause a "Mini-cycle" as filter bacteria are killed off.
  • Many fish are sensitive to types of Antibiotics, meaning their use puts stress on the tank's inhabitants. Just like us, Antibiotics can kill of the good bacteria in a fish's body, leaving it stressed and prone to other types of illnesses.
  • Over-prescription of Antibiotics may make it more difficult to possess them in the future, when they may be truly required.
  • Antibiotics must be dosed at their full recommended dosage, and courses cannot end early. To under-dose or to end a course early increases the likelihood of resistance against the medication in the future. This also means they cannot be "half-dosed" when used on scaleless or sensitive fish.

 

This is not to say "don't use them"! Antibiotics are often essential for bacterial diseases, and can be immensely useful to have on hand. We simply recommend being sure of a diagnosis before using Antibiotics on fish.

Dosage of Antibiotics is typically done by treating the whole tank or the isolated fish, however in some cases, medicating food or doing short-term baths on the affected fish may be the most efficient way to dose a tank, and this also helps to reduce the overall dosage size needed.

 

Conclusion

We truly hope that this article may be of some help and guidance for understanding treatment for your situation, and are more than happy to take on suggestions and advice of your own. If you have any questions or comments, feel free to comment below or Contact Us.

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