Fin Rot 101:
Ragged rot
cant be seen on edges
of fins.
Class is in session, this is Fin Rot 101!
Let's face it, we've all probably encountered fin rot at some point. Even the most experienced keepers have battled it before. Fin rot is a very common disease found in betta tanks, so here's a guide on how to recognize, treat, and prevent fin rot.
Let's get started on what exactly fin rot is.
Fin rot is caused by bacteria that is living in your fish tank. All tanks have this bacteria in them, and its's not inherently dangerous. What makes this bacteria dangerous is when the tank is not clean, if it is over stocked, or if the fish is injured or stressed. The bacteria that causes fin rot can be many different types of bacteria.
Fin rot is commonly found in Pet Store bought fish, who usually have damage to their fins because of stress and neglect.
Breathe a sigh of relief, because fin rot can be treated with a bit of extra TLC and diligence.
Let's face it, we've all probably encountered fin rot at some point. Even the most experienced keepers have battled it before. Fin rot is a very common disease found in betta tanks, so here's a guide on how to recognize, treat, and prevent fin rot.
Let's get started on what exactly fin rot is.
Fin rot is caused by bacteria that is living in your fish tank. All tanks have this bacteria in them, and its's not inherently dangerous. What makes this bacteria dangerous is when the tank is not clean, if it is over stocked, or if the fish is injured or stressed. The bacteria that causes fin rot can be many different types of bacteria.
Fin rot is commonly found in Pet Store bought fish, who usually have damage to their fins because of stress and neglect.
Breathe a sigh of relief, because fin rot can be treated with a bit of extra TLC and diligence.
Recognizing fin rot:
Severe, black rot.
Fin rot can be tricky to spot on your betta, especially if they have dark fins, if it is a mild case, or if the fish is a crown tail. There are, however, tell-tale signs your fish's fins are being eaten by this pesky bacteria.
First, assess your tank.
Be honest with yourself. Are you cleaning the tank enough, is the water frequently changed for the tank's size? Is your fish living with tank mates that it shouldn't be, or living with too many other fish? These issues are critical to relieving fin rot, as the fin rot will not go away unless the tank is kept clean and not over stocked.
Do your fish's fins appear damaged?
Are your fish's fins...
First, assess your tank.
Be honest with yourself. Are you cleaning the tank enough, is the water frequently changed for the tank's size? Is your fish living with tank mates that it shouldn't be, or living with too many other fish? These issues are critical to relieving fin rot, as the fin rot will not go away unless the tank is kept clean and not over stocked.
Do your fish's fins appear damaged?
Are your fish's fins...
- Ripped looking?
- Bright red at the tips or around tears?
- Dull and grey or brown/black, and not part of their natural coloring?
- Fuzzy at the tips or around injuries?
- Beginning or already receding towards the fish's body?
- Frayed or tattered looking?
Rotting black tips.
Next, try to gauge how severe the rot is, if you believe it is present:
Mild fin rot is...
Major fin rot is...
Extreme fin rot is...
Actually no longer "fin" rot at all. Fin rot that has been left to get really bad can turn into Body Rot.
Body rot is serious and needs to be dealt with quickly. Signs of Body rot are fins that receded to the body, which are now being eaten away at, fuzziness, fins are gone.
Gauging how severe you fish's fin rot is important to how to treat your fish. If you believe your fish has...
Mild to Mild-Moderate fin rot, please use the information located under "Mild" Fin Rot.
Moderate to Major fin rot, please use the information located under "Major" Fin Rot.
The difference between this information will be how aggressively to treat the fish's disease.
Mild fin rot is...
- Mild tattering on the fins, some tattering
- Slightly darker in color or turning grey/brown at the tips
- Only present on the tips of the fins, not near the body
- Small amounts of redness at the fin tips/ some irritation
Major fin rot is...
- Intense damage of the fins, rips, tears, chunks missing (not from a fight)
- VERY dark coloration, very dark or grey, appears very clearly that the fin is beginning to die.
- Appears in large sections of the fins, beyond just the tips, more than 1.5cm of fin death.
- Fins have sharply receded towards the body
- Fins appear bloody and red in many spots or are covered in "fuzz"
Extreme fin rot is...
Actually no longer "fin" rot at all. Fin rot that has been left to get really bad can turn into Body Rot.
Body rot is serious and needs to be dealt with quickly. Signs of Body rot are fins that receded to the body, which are now being eaten away at, fuzziness, fins are gone.
Gauging how severe you fish's fin rot is important to how to treat your fish. If you believe your fish has...
Mild to Mild-Moderate fin rot, please use the information located under "Mild" Fin Rot.
Moderate to Major fin rot, please use the information located under "Major" Fin Rot.
The difference between this information will be how aggressively to treat the fish's disease.
What to do for both types:
A small QT tank, heated.
Here's what to do first:
- "Quarantine" your fish if it lives in a tank over two gallons, lives with other fish or snails, or if it lives with live plants.
- If your fish is in a tank larger than two gallons, etc. find another container that is clean and safe to treat the fish in. This allows you to not need to do as large of water changes, spares other fish from being harmed, and saves plants from medicines that may kill them.
- Try to keep the "QT" tank .5 gallons-2 gallons, as it is easier to dose medicines this way.
- If the fish has a small QT home, consider floating it in the original tank to keep the fish warm. You can tape the QT container against the tank. Doing so will prevent the QT from tipping or being knocked around. Take care that if it has a lid with holes that it doesn't flip over, which will drown the betta.
- Larger QT tanks should be heated via a heater, if they cannot bob in the main tank.
Now that the fish has a temporary home to be treated in, you need to focus on the water:
- Put new, clean water in the QT tank. This helps get rid of or discourage bacterial growth. Be sure to properly acclimate the fish when adding it into this temporary home.
- Try and keep the water the QT tank in at or around 76-78'F. This range discourages the spread of bacterial growth. When higher, it encourages growth, and when under 76'F, it is not safe for a betta.
- Consider keeping the lights off in the tank, shut the filter off ( if you are treating in-tank), as the current will hinder fin regrowth and the carbon in the filter media will take out medicines in the water and make them ineffective.
Aquarium Salt
Now for the "medicine":
The most effective medicine that you can use to cure fin rot at a mild stage is clean water and Aquarium Salt.
AQ Salt is sodium chloride, which heals open wounds and helps de-stress fish. Aquarium Salt is commonly found in many pet stores and is not expensive.
Like with any medicine, AQ salt should not be used for prolonged periods of time or in very high doses. Ten days is the maximum amount of time you should treat a fish with AQ Salt. Prolonged use can cause kidney and liver damage. Also, like any other medicine, the appropriate dose should be used. Do not use AQ salt as a "preventative" medicine at a low dose, as it will eventually become less effective and diseases will become resistant to it. For example, when 1tsp/gallon of water is needed, do not use .5tsp/gallon. Its like taking a half an aspirin when you need three:; it doesn't do anything!
The most effective medicine that you can use to cure fin rot at a mild stage is clean water and Aquarium Salt.
AQ Salt is sodium chloride, which heals open wounds and helps de-stress fish. Aquarium Salt is commonly found in many pet stores and is not expensive.
Like with any medicine, AQ salt should not be used for prolonged periods of time or in very high doses. Ten days is the maximum amount of time you should treat a fish with AQ Salt. Prolonged use can cause kidney and liver damage. Also, like any other medicine, the appropriate dose should be used. Do not use AQ salt as a "preventative" medicine at a low dose, as it will eventually become less effective and diseases will become resistant to it. For example, when 1tsp/gallon of water is needed, do not use .5tsp/gallon. Its like taking a half an aspirin when you need three:; it doesn't do anything!
Mild Fin Rot- Treatment:
Rot after injury (top).
To treat mild rot with AQ Salt in your quarantine tank:
- Take a clean cup of some sort to mix clean tank water and salt in. Take a small amount of the QT tank's water out and into this cup. You're mixing the salt before hand because when not dissolved, it burns!
- Add in 1 teaspoon per gallon of Aquarium Salt into this cup and allow it to dissolve fully. Stir it around to mix faster. So, if you have 1/2 gallon of water, .5tsp; 1 gallon of water, use 1 tsp of salt; 2 gallons, 2 tsp of salt; and so on. This is why you use a smaller container, its easier!
- If the fin rot is a bit more advanced- mild-moderate- up this dose to no more than 1.5 tsp salt/gallon of water. Pre-mix it in the water like above.
- Add the salt/water mixture back into the QT tank gently so it wont knock around your fish.
Your fish now has all the medicine it needs to cure its fin rot. Stay away from unnatural remedies, as these can be dangerous when not dosed correctly. Salt and clean water does wonders.
After one day, do a full, 100% water change in your QT tank. This is important because it keeps bacteria growth down, provides a clean environment for the fish, and makes re-dosing the salt easier. After a 100% water change (100%!!!), re-dose the 1tsp/gallon of AQ salt. Acclimate your fish properly and gently each time you do.
DO NOT COMPOUND THE SALT DOSES EACH DAY. Do NOT add 1 tsp one day, 1 tsp the next, etc, while not changing the water. It will kill your fish!
Afterwards
Once your fish has received a 7-10 day treatment with 1-1.5tsp/gallon of Aquarium salt with daily 100% water changes, it should be healing. It may take a little bit to see fin re-growth, but it will be worth the wait when it comes. Re-growth appears clear at the ends and will usually regain color.
Make sure the fish's filter remains off for a while to promote fin re-growth. Also, keep the tank's water changes a bit more frequent than usual while it heals, for good measure.
Make sure the fish's filter remains off for a while to promote fin re-growth. Also, keep the tank's water changes a bit more frequent than usual while it heals, for good measure.
Quick Reference For Mild Fin Rot:
Put the fish into a clean quarantine tank and do a 100% water change in that tank. Keep the tank dark and at 76-78'F if you can. Float it in the "big" tank to keep it warm. Add in 1tsp/gallon of Aquarium Salt, pre-mixed beforehand into the tank. For slightly more severe rot, use 1.5tsp/gallon of the salt. Do 100% daily water changes each day and re-dose only after the 100% change, for no more than 10 days. After that time, turn off the filter to aid in fin regrowth and up the water changes for a bit.
Major Fin Rot- Treatment:
Severe rot caused by injury.
Fin rot that is severe needs to be treated more aggressively than mild rot. Sometimes, fin rot will no longer begin to respond to salt treatments. Once the fish has been treated for rot but it comes back and isn't responsive, please follow the second set of directions.
To treat with AQ Salt in your quarantine tank:
Your fish now has all the medicine it needs to cure its fin rot. Stay away from unnatural remedies, as these can be dangerous when not dosed correctly. Salt and clean water does wonders.
After one day, do a full, 100% water change in your QT tank. This is important because it keeps bacteria growth down, provides a clean environment for the fish, and makes re-dosing the salt easier. After a 100% water change (100%!!!), re-dose the 2 tsp/gallon of AQ salt, adding another 1tsp/gallon after an hour. Acclimate your fish properly and gently each time you do.
DO NOT COMPOUND THE SALT DOSES EACH DAY. Do NOT add 3 tsp one day, 3 tsp the next, etc, while not changing the water. It will kill your fish!
To treat with AQ Salt in your quarantine tank:
- Take a clean cup of some sort to mix clean tank water and salt in. Take a small amount of the QT tank's water out and into this cup. You're mixing the salt before hand because when not dissolved, it burns!
- Add in 2 teaspoons per gallon of Aquarium Salt into this cup and allow it to dissolve fully. Stir it around to mix faster.
- If the fin rot is very advanced, up this dose to no more than 3 tsp salt/gallon of water. Pre-mix in 2 tsp as above. After 1 hour, add in one more tsp/gallon of the salt. You are staggering the amount to assure the fish isn't stressed by so much salt. (In total, this will equate to 3 tsp/gallons. So, if you have a 1 gallon tank, you've added 2tsp at first. Later, you add 1 more tsp, for a total of 3 tsp.)
- Add the salt/water mixture back into the QT tank gently so it wont knock around your fish.
Your fish now has all the medicine it needs to cure its fin rot. Stay away from unnatural remedies, as these can be dangerous when not dosed correctly. Salt and clean water does wonders.
After one day, do a full, 100% water change in your QT tank. This is important because it keeps bacteria growth down, provides a clean environment for the fish, and makes re-dosing the salt easier. After a 100% water change (100%!!!), re-dose the 2 tsp/gallon of AQ salt, adding another 1tsp/gallon after an hour. Acclimate your fish properly and gently each time you do.
DO NOT COMPOUND THE SALT DOSES EACH DAY. Do NOT add 3 tsp one day, 3 tsp the next, etc, while not changing the water. It will kill your fish!
.Quick reference for Major Fin Rot:
Put the fish into a clean quarantine tank and do a 100% water change in that tank. Keep the tank dark and at 76-78'F if you can. Float it in the "big" tank to keep it warm. Add in 2tsp/gallon of Aquarium Salt, pre-mixed beforehand into the tank. For more severe rot, use 3tsp/gallon of the salt, add in the first 2tsp/gallon at once and then the next 1tsp/gallon one hr later. Do 100% daily water changes each day and re-dose only after the 100% change, for no more than 10 days. After that time, turn off the filter to aid in fin regrowth and up the water changes for a bit.
Severe Fin Rot/ Resistant Rot- Treatment:
Sometimes, fin rot just wont go away, even with proper water changes and salt. It is possible that the bacteria responsible for this rot is resistant or does not respond to salt treatments. After trying to get rid of the rot with 2-3 tsp/gallon of salt, as above, nothing is working or it returns quickly, medicines should be considered to treat your fish.
PLEASE. Be honest with yourself. If your fish is still in poor living conditions, with too few water changes or too many tank mates, your rot will not get better. YOU need to take out the tank mates for good if there are too many and YOU need to keep up with proper water changes. You can treat and treat, even with medicines, but if these issues are not addressed; it will not be fixed.
That said, if you are experiencing the above, try using medicines. Medicines, like those listed below, help get rid of fin rot by usually using antibiotics. These medicines should be used sparingly, just as in humans, to avoid creating resistant bacteria.
These medications are widely available and will help in treating your fish's fin rot when resistant. Please follow the correct and appropriate dosing and water change schedule as per the label. DO NOT use these medicines in combination with other medicines unless directed otherwise by the label.
Before adding ANY medicines to the tank, please remove your carbon from your filter, as it will suck up all the medicine, and do a 100% water change. This is to avoid having water parameters that can make medicines toxic. If you can, add an air/bubble stone to increase oxygenation in the water, which will be sucked out by the medicines.
- Maracyn II (Two) is an antibiotic that attacks gram-negative bacteria, which is typically the bacteria that causes this kind of rot. It can be found in most places that sell fish supplies, like Petsmart. It is made by Mardel.
Update: Unfortunately, the Maracyn series is no longer being made. Make sure yours is within date if you have it or are able to still buy it. - Maracyn (I) is also an antibiotic, but this one attack gram-positive bacteria. Because these bacteria are not usually responsible for resistant fin rot, this product should not be used by itself. Use with Maracyn II at the same time (Yes, you can do this), to help fight other diseases that may be present now that the fish's body is being attacked. You do not need to use both, but don't use just this one. It can be found in many places like above and is also made by Mardel.
Update: Unfortunately, the Maracyn series is no longer being made. Make sure yours is within date if you have it or are able to still buy it.
- Jungle Fungus Eliminator, Jungle Fungus Clear is a good product for treating aggressive rot, as well as many other diseases. The two downsides to this medicine are that it changes the water's color DRASTICALLY (blue/green) and, when purchased in tablet form, it is made for 10gallons/tab. To shorten the dose, use scissors and scratch along the tablet in half, quarters, etc, then break. Like Maracyn, it is widely available, even in Wal*marts, as well as Petsmarts, etc. Made by Jungle, and can also be found in powder form.
- Erythromycin (try: API Brand) is an antibiotic that can work against fin rot. like Jungle Fungus clear above, it may be hard to dose in tablet or powder form if you are dosing for a smaller tank. It should not discolor your tank's water or decor. This item is expensive: USD ~$17 and can be found at Petsmarts, and similar stores.
- Tetracycline (try: API Brand) is an antibiotic that can work against fin rot, but may not work as well as other medicines. If you can get it, try it. Please note potential issues with dosing as stated above. This item may discolor your water, but should be okay for decor. This item is expensive: USD ~$16 and can be found at Petsmarts, and similar stores.
- API Fungus Clear is a slightly less expensive option for treating rot. Please see potential problems with dosing as noted above. This product may slightly discolor your water but should be okay for decor. This item is of moderate price: USD ~$12 and can be found at Petsmarts, and similar stores.
- Other medicines, such as minocycline, Kenacyn/kanamycin, tetracycline, and many others are available under various names, sometimes generic ones. They can be found in fish stores, usually. You can also try your hand at Amazon.com if you feel comfortable with waiting for shipping.
Note: Unfortunately, it seems that fish medicine is shifting to more expensive options with quality brands in more stores. You may find yourself spending quite a bit on medicines in big-box stores because of this. Many manufacturers are switching to "all-in-one" medicines that aren't as high of quality or effective as their predecessors. Please use your best judgement and consider your budget when choosing!
Avoid medicines that have melalecula oil (tea tree oil) in them, as they DO NOT treat fin rot. They are antiseptic medicines that will help AFTER the rot is cured and help with fin re-growth in some fish. Such medicines are Melafix and Bettafix, to name a few. These medicines are controversial in the betta community, as too much of this medicine can cause damage to their labyrinth organ/lungs. This site does not encourage their use in these fish. Please avoid their use per the recommendation of this article and its treatments.
Please your best judgement when treating Fin Rot. The best way to prevent this painful disease is to keep your fish in clean water, without too many tankmates or too much stress, feed it well, and keep it warm. Good luck!