Five Quick and Easy Steps to Treat Fin Rot

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Five Quick and Easy Steps to Treat Fin Rot

What do you do if your fish’s fins and tail are looking ragged or discolored? Fin rot is a bacterial infection. Although it is easy to treat, this illness can cause serious complications if not treated promptly. Follow our five simple steps to cure fin rot.


How Do I Know If My Fish Has Fin Rot?

Fin rot is commonly found in aquarium fish such as betta fish and goldfish. The symptoms can vary based on how long the fish has been affected:

Stage I:

There is some discoloration around the edges and fins/tail. Depending on the original color of the fish, the discoloration may appear as white, red, or even black. Stage 2

The fin edges look frayed and uneven as infected pieces start to die and fall off. Stage 3

The whole tail and/or fin has been rotted, and the infection can spread to the entire body, possibly leading to death.

You may also notice your fish seems listless or doesn’t feel like eating anymore, since its body is working hard to fight the infection.

If your fish naturally has uneven fin edges, you may have difficulty spotting fin rot.

How Do You Treat Fin Rot in Fish?


Check your fish’s environment

Whenever your fish gets sick, the first thing you need to do is play detective and find out why the fish got sick. If you don’t fix the problem, fin rot can return. Check the water parameters with an aquarium water test kit to see if anything is out of whack. Make sure there are no environmental factors causing stress to your fish, like an overly strong filter, sharp decor, or wrong temperature. 2. Use corrective measures

After you discover what’s wrong, remove the source of stress immediately so your fish can start recovering. 3. Clean the fish tank

Medications often require you to hold back from doing water changes during treatment, so clean the aquarium and remove as much fish waste as possible. (Read our tutorial on how to properly clean your aquarium.) 4. Combine with medications

A broad-spectrum antibiotic called erythromycin is recommended to combat fin rot. If your fish has also developed a secondary fungal infection, methylene blue is an appropriate antifungal treatment. 5. Make your fish very comfortable

Keep your fish’s environment very clean and comfortable to ensure a quick recovery process. To ensure that your fish are comfortable, you can add an air filter or sponge filter to the water.

If you cannot buy erythromycin in your country, try treating the fin rot with aquarium salt. It is usually more difficult to treat the infection with this method. For more details, read our full article on how to treat fish diseases with salt.

Fin rot can be caused by dirty water, nipping from other fish, or other stress factors.

How can you tell if finrot is cooked?

The medication may take several days to beat the infection, but some clear signs of recovery include:

– The fin rot has not progressed – No other new symptoms have appeared – Your fish’s appetite and energy level are returning – Fin regrowth has begun (and may be a different color than before)

You can take steps to prevent fin rot returning. Dirty water is a common cause for bacterial infection, so schedule a regular time for cleaning the aquarium and put a weekly reminder in your phone so you won’t forget. Other ways you can keep the water cleaner include not putting too many fish in one aquarium, not overfeeding them, and adding live plants to help absorb some of the fish waste.

As mentioned before, continue to reduce any stress factors in the aquarium by maintaining the proper temperature with a heater, slowing the water current if needed, and removing any aggressive tankmates. Finally, keep a close eye on your fish. It’s easy to miss symptoms if no one’s paying attention to the aquarium, so we recommend examining your fish once a day when you feed them.

Be encouraged! With proper treatment and prevention, fin rot is an easy sickness to beat, and most healthy fish have no problems making a full recovery. For information on how to treat other fish diseases, see our other articles here:


– Fin Rot on Betta Fish by Dizzy Respect with color adjustment (CC BY-SA 4.0) – Betta Half Moon by Lerdsuwa with cropping (CC BY-SA 3.0) – Green tiger barb by Debivort with color adjustment and cropping (CC BY-SA 3.0)