How to Treat Fin Rot in Angelfish: 9 Best Treatments

Fin rot is a very common disease that infects angel fish. If not treated your angel fish will become very poorly.

Fin rot is highly contagious and it is very important to treat your whole tank as soon as you can.

Fin Rot in Angelfish

Symptoms of Fin Rot

Signs your angel fish has fin rot are

  1. Fins Turn Light / Milky Colour : The first signs that your angel fish is suffering with fin rot is that the edges of the fins will turn a light / milky colour
  2. Fins Start To Fray : The next symptom will be fraying of the fins, as the infection spreads small parts of the fish fins will die and come off leaving a rough edge
  3. Shorter Fins : Over time the fins will become shorter and shorter
  4. Inflamed Fins : In the later stages of fin rot the fins will become inflamed and will become red

With this disease it is very important to catch it in the early stages as it can do a lot of damage to the fish.

Causes of Fin Rot

What causes fin rot in angel fish? The most common cause of fin rot in angel fish is poor water quality.  This will enable fungus and bacteria to enter your tank and will attach to your fish.  The tempreature of your tank also has a big impact.

Conditions that will increase the risk of fin rot are

  1. Poor water quality
  2. Low water tempreature
  3. High Ph level
  4. Nippy fish in tank


With this disease it is very important to treat it as soon as you can.  The earlier you act the better chance your fish has of making a full recovery.

It is important to identify the root cause of the issue and resolve it.  The most likely is poor water condition.

To treat fin rot in angel fish try the following solutions

Improve The Water Quality

If water quality is the root cause we need to address this issue because your fish could get sick again after the fin rot has gone.

The first thing that should be done is to change 50% of the water.  This will remove around 50% of any fungus and bacteria that are in your tank. Also clean the filters in your pump to make sure the water is being filtered correctly.

If you have gravel in your tank make sure to clean that as well with something like an Aquarium Gravel Cleaner (Available on amazon)

Are you over feeding your angel fish?  Left over food will decay and will introduce bacteria in to your tank.  It is very important not to over feed them.  You should feed them 3 times a day and give them enough food that they can eat for 30 seconds.

feeding angel fish

Check Water Temperature

Angel fish are tropical fish and require to be kept in warmer water in the range of 77 to 83f.  Angel fish will survive in lower water temperatures but they will not thrive. They will be more likely to develop diseases such as fin rot in lower water temperatures.

It is recommended to use an aquarium heater (Available to buy on amazon) to keep your aquariums temperature at the recommended level.

Test Water Quality

I also recommend that you use a aquarium water test kit (Available to buy on amazon) on your aquarium’s water.  It will show you information about the below

  • pH Level
  • Nitrite
  • Nitrate carbonate
  • Water hardness

Using this test kit will give you peace of mind if the water quality is healthy or not.

Test Water Quality

Over Populated

An over populated aquarium will produce poor water conditions.  Check the amount of fish you have in your tank against how many gallons your tank has.  If your tank is over populated it is recommend to move some fish to another tank or to do more frequent water changes.

Quarantine Infected Fish

If only a few of your angel fish are infected with fish rot you should move them in to their own tank to prevent them spreading this disease to the other fish in your tank.

You can then treat the infected angel fish and move them back in to the original tank when they are cured.

Quarantine Infected Fish

Antibiotics and Antifungals

Now we have resolved the environmental issue we can treat the angel fish for fin rot.  The antibiotics you can get for fish will not only cure fin rot it will also cure many other diseases your fish might have.

I recommend that you use something like Fungus Clear (Available on amazon) to treat this disease.  All you need to do is drop a tablet in the water and it will dissolve and your fish will take in the medicine. (Always make sure to read the instructions before use)

If you are giving your fish antibiotics you will need to perform a water change to the tank daily.

Aquarium Salt

Adding aquarium salt to your tank will help the water to get rid of fungus and bacteria.  It will also help to heal any open wounds.

You will need to add one table spoon of salt for every three gallons of water.

I recommend to dissolve the salt in a cup of water before adding it to your tank.

Add Fast Growing Plants

By adding fast growing plants to your tank it will help to reduce the nutrients available to the algae and bacteria.  This is a great way to help to maintain ideal water conditions in your tank.

Fast growing plants include

  • Java moss
  • Lilaeopsis
  • Hornwort
  • Amazon Sword
  • Water Wisteria

fast growing aquarium plants


If your fish have suffered from fin rot disease you will want to take measures to prevent it from returning in the future.

So How to prevent Fin Rot in Angelfish? The best prevention against fin rot is to make sure the aquarium’s water is well maintained. This can be done by doing regular water changes, Making sure the filter is cleaned regularly and checking the water condition with a tester weekly.


Below are the frequently asked questions about this disease

Does Aquarium Salt Help For Fin Rot? Yes it does, aquarium salt will help to reduce the amount of fungus and bacteria in the water, It will also help to heal any open wounds that the angel fish might have.

How long does fin rot take to heal? It will take 4 – 5 days for fin rot to heal when you have started an antibiotics treatment. When applying the treatment you will need to perform daily water changes in your tank as this will help to reduce the risk of re-infection.

Can Fin Rot Heal On Its Own? Yes fin rot can heal on its own as long as the water conditions are healthy and the fin rot is in the early stages.  If your fish is in the later stages of fin rot they will require an antibiotics treatment.

How To Tell If Fin Rot Is Getting Better? Your angel fish will be recovering from fin rot disease if the colour to their fins are returning or the whitening has disappeared.  The fins should also look a lot healthier (not frayed) and the fins are no longer inflamed.

Can Angel Fish Recover From Fin Rot? Yes fin rot can heal on its own as long as the water conditions are healthy and the fin rot is in the early stages.  If your fish is in the later stages of fin rot they will require an antibiotics treatment.