We love our fish as our babies, don’t we? So when they are sick, we feel for them. A very common fish problem is betta fish fin rot. What is it? What are the symptoms? How do we treat it? Let’s find out!

What is Fin Rot?

Betta Fin Rot

Betta Fish Fin Rot

According to Betta Splendid, betta fish fin rot is a bacterial disease which can be caused by a few different types of bacteria. Bacteria live everywhere, and the bacteria in question lives in fish tanks. It’s generally not harmful, just as most of the bacteria in our body are not harmful, but it could become dangerous if a few factors go wrong:

* The tank has too many fish.

* The tank is not properly cleaned.

* The fish in the tank are stressed or hurt.

Fin rot is more common in store-bought fish as the living conditions in pet shops are less than ideal and the factors listed above are more likely to happen. Either way, keep your eyes peeled!

How Do We Spot Fin Rot?

fin and tail rot betta fish

fin and tail rot betta fish

Sometimes it’s not easy to notice fin rot, especially if the fins of your babies are already quite dark. You have to be extra careful to pick up the signs:

* Don’t worry, we won’t judge, but let’s have a look at your tank:

– How clean is it?

– Is there enough water?

– Do you change the water enough?

– How well do your babies get on?

– Are there too many?

* It’s OK to stare lovingly at your pets. How do the fins of your babies look?

– Are they ripped?

– Do the tips or areas surrounding any injuries appear unnaturally bright red, grey or black?

– Are the tips or areas surrounding any injuries fuzzy? Frayed? Tattered?

– Do the fins seem to be receding into the body?

Also, does your baby look lethargic?

Betta Fish Fin Rot

How bad is it the betta fish fin rot?

Minor Fin Rot

Don’t panic if the fins:

– are only a little tattered.

– are just a little bit darker or a little bit red.

– are only dark at the tips.

Major Fin Rot

It’s time to worry if:

– the fins are very torn or have large chunks missing from them.

– the discolouration is very obvious and all over the fin.

– the fin looks bloody or are fuzzy.

– the recession is very pronounced.

– the fin actually looks like it’s dying.

Extreme Fin Rot

Now you can turn on freak-out mode!

Extreme fin rot may turn into body rot:

– There is no more fin left so see.

– The body itself is losing definition.


Whether it’s mild, major or extreme, you have to do these things pronto:


– Stick your poor baby into quarantine if it lives with any kind of friends, live plants or in a tank larger than 7.5 liters.

– Use a 1.9 liter – 7.5 liter tank for your quarantine bay so that it’s easier to measure out medicine dosage.

– If your quarantine tank is much smaller than your baby’s usual home, try sinking the quarantine home into the large one to keep it warm. Tape the smaller tank onto the wall of the larger one so that it doesn’t move about.

– Fill your baby’s temporary home with clean, unchlorinated water.

– If you can’t sink the quarantine home into the normal home, heat its water with a heater. Keep the temperature around 25°C to avoid bacterial growth.

– If your baby is quarantined in its own temporary home, don’t place any lights or filters in it as lights will encourage bacterial growth and filters will remove the medicine, as well as cause currents that will get in the way of fin growth.

– If your baby didn’t have any friends in their home, empty out the water and clean the tank and everything in it. If there are other friends or live plants, drain as much of the water as possible, then refill with clean water, cycling this a few times. Wiki How recommends checking the pH of the water with a pH test kit – it should be 7-8 pH, with zero nitrate, nitrate and ammonia levels at 40ppm.

– You should wash the filter in a bucket of fresh tank water (not tap water) too.

Now to get your baby all better.

Mild Fin Rot

Don’t worry, it’s easy to cure mild fin rot.

– Put your baby in clean water treated with aquarium salt (sodium chloride). Aquarium salt is like betadine for fish – it treats wounds. It also de-stresses your baby.

– 10 days should do the trick but even if it doesn’t, don’t go past 10 days as it can cause kidney or liver damage. As with all medications, use as directed.

– Using a clean cup, scoop some of the quarantine tank water.

– Stir in 1 tea spoon of Aquarium Salt per gallon of water, completely dissolving it. You have to dissolve the salt first, otherwise it will burn your poor baby!

A rough guide:

1.9 liter water, 0.5 tea spoon salt

3.78 liter water, 1 tea spoon salt

7.5 liter water, 2 tea spoons salt

– Slowly pour the mixture back into your baby’s quarantine tank.

– Use an air pump or air stone to circulate more oxygen in the tank as medication can deoxygenate water. Put in on low to avoid stressing your baby out.

– Wait 24 hours, then change ALL of the water in the quarantine tank to avoid bacteria, keep your baby’s environment clean and make it easier to put in a new batch of Aquarium Salt.

– Put in the same amount of salt as you did the first time. It’s super important that you change ALL of the water so that you’re not adding more salt into what’s already there … too much salt will kill your baby!

– Repeat this treatment for 7-10 days. You should start to see the fin growing back – it will start off clear and then color in.

– Continue to keep the filter off and changing the water more frequently until you feel your baby is healed.

Major Fin Rot

The treatment for major fin rot is more aggressive.

– As with minor fin rot, scoop out some of the quarantine tank water.

– Stir in up to 3 tea spoon of Aquarium Salt per gallon of water, depending on how severe the rot is. If you choose to go for 3 tea spoon, mix and pour in 2 tea spoon first, wait for an hour, then add the last tspn of salt in. This is so that you don’t over-stress your baby with too much salt at a time.

– Continue the treatment as you would for mild fin rot.

Extreme or Recurring Fin Rot

If the bacteria just won’t quit despite the diligent care you’ve taken. It’s time to consider medication. There are several medications for betta fish fin rot:

Erythromycin (recommended brand: API Brand)

Erythromycin API Brand

Erythromycin API Brand

– It may be hard to dose a smaller tank as it is in tablet or powder form. A good gauge of when to stop would be if the water or decorations discolor.

– This medication is on the expensive side.

Jungle Fungus Eliminator/Clear (Jungle Brand)

Jungle Fungus Eliminator Jungle Brand

Jungle Fungus Eliminator ( Jungle Brand)

– This works well for many fish diseases include betta fish fin rot.

– It colors the water to a very obvious bluish-green.

– The tablets are most suited for 10 gallons per tab. You have to break the tablet into halves or quarters (use a blade to score the tablet to break it easily if you don’t have a tablet cutter.) Opt for the powder if you can.

API Fungus Clear

API Fungus Clear

API Furan -2

– This medication has pretty much the same properties as the previously mentioned medications.

– API Fungus Clear is cheaper.

Tetracycline (recommended brand: API Brand)

Tetracycline API brand


– Is similar to the other medications, but is on the expensive side and may not be as effective.

Most medications for fin rot are antibiotic. DO NOT use TEA TREE OIL (melaleuca oil) medication as they only facilitate healing – they don’t treat the problem. They can also cause lung problems. Make sure you follow all directions to the ‘t’. Make sure you’ve taken the carbon out of the filter too, otherwise all the medication will be cleaned out before it has a chance to work.

All in all, prevention is better than cure. Do these basics and you can stop your babies from getting fin rot:

* Keep it clean – change the water once a week.

* Keep it spacious – avoid overcrowding the tank.

* Keep it friendly – make sure all the fish living together get along.

* Keep them fed – feed your fish consistently with good food. Try to vary the food.



Content Inspires by the following resources

  1. http://bettasplendid.weebly.com/fin-rot-101.html
  2. https://www.youtube.com/watch?v=KVOhl7a8eWc
  3. https://www.pinterest.com/pin/276056652135888447/
  4. https://au.pinterest.com/tishvanarsdale/fish/
  5. https://www.pinterest.com/cbetancourt91/quarantine-tank/
  6. https://www.amazon.com/Jungle-TB630W-Buddies-Tablets-8-Count/dp/B0002561WY
  7. http://www.wikihow.com/Treat-Fin-Rot
  8. http://www.bettafishcenter.com/Fin-Rot.shtml
  9. https://www.thespruce.com/fin-rot-1378481
  10. https://bettafish.org/diseases/fin-rot/