Betta Fish Fin Rot: Complete Guide

Betta, Care, Disease, Fin Rot, Fish -

Betta Fish Fin Rot: Complete Guide

Quick Overview

  • Common Name: Fin Rot, Tail Rot, Fin Melt 
  • Different Types Of Fin Rot: Bacterial Fin Rot & Fungal Fin Rot
  • Severity: Mild, Moderate, Severe Fin Rot
  • Causes: Poor Water Quality, Physical Injury, Poor Diet, Stress, Secondary Infection
  • Symptoms: Fin edges losing color, Fins Frayed, Vase of Fins Inflamed, Fins Missing, Fuzzy Growth
  • Treatment:  Depends On The Severity Of Fin Rot & Type Of Fin Rot ( Aquarium Salt, Frequent Dechlorinated Water Changes, BettaFix & Other Betta appropriate Medication)   
  • Prevention: Frequent Dechlorinated Water Changes, Proper Diet, Proper Temperature, Remove possible causes of physical injuries (Hard decorations,Nippy fish, Filters with Strong flow)  
Betta Fin Rot

It happened so suddenly, you were watching your betta fish swimming around one day and you noticed that his fins looked a little off. Looking closer it’s apparent that your betta’s long fins are missing, frayed or maybe losing their vibrant color. If this sounds like a familiar scenario, your betta fish might be suffering from fin rot or fin loss.

What Is Betta Fin Rot?

Betta Fin Rot

Fin rot is a common preventable aquarium disease seen in betta fish. Fin rot is usually caused by gram-negative bacterial or fungal pathogens. These pathogens are naturally present in aquarium water. Most of the time, if your betta fish is in good health, their immune system will protect them from these diseases. If your betta fish is in poor health, they are highly susceptible to fin rot due to their long delicate finnage.

What Causes Betta Fin rot?

Fin rot is actually very common among bettas. Most new betta owners keep their tank in poor water conditions. Things like an unheated tank, overcrowding, and uncycled aquarium can all cause an outbreak of fin rot. These stressors will add up, weakening a betta’s immune system just enough so that the bacteria and fungal pathogens can infect your fish.

What are some symptoms of betta fin rot?

Betta Fin Rot can be broken down into three main stages. This all depends on how long the betta has been infected. As with all infections the earlier you notice and treat the disease the better the outlook on the betta’s health will be. If left untreated, it’s possible for the fin rot to affect the betta’s body.  

  • Mild Fin Rot: Symptoms of Mild Fin Rot can include brown or black tips at the edges of the betta’s fins, jagged fin edges, whitish tips or spots if they are infected with a fungal infection.
  • Moderate Fin Rot: Signs of Moderate Fin Rot can include Large Fin Reduction, Fins Turning Black, Fin Edges Developing White Patches & Fuzzy Growth or Hairs.
  • Severe Fin Rot: Symptoms of Severe Fin Rot can include Increased deterioration of fins, redness at the fish’s body, entire loss of fin, body rotting, swimming difficulty and more.

How Do I Treat Betta Fin Rot?

It depends at what stage the betta’s fin rot is in.  First off, if you think that your fish is in the mild fin rot stage, the best course of action, in my opinion, would be to step up on those water changes! Along with that, you might want to add some aquarium salt to the tank. If the fin rot is more advanced I would still recommend more water changes and salt. However, start thinking about using a medication as well.  Using meds can be tricky, I suggest that you always read and follow the directions of all medications that you might buy.

Try using medication like Bettafix or API Fin & BODY CURE. I only recommend medication as a last resort and if your betta has moderate to severe fin rot.

How Do I Prevent Betta Fin Rot?

Healthy Betta Fish

The best way to avoid betta fin rot altogether would be to reduce as many stressors for your betta fish. Things like correct tank size, a heated tank, cycled aquarium, a proper diet will all help prevent your betta fish from contracting fin rot.

  • Cycled Aquarium: A cycled aquarium is an important process that all new fish owners should know. But, to put it simply fish poop. That waste builds up in the form of toxic ammonia.  A cycled aquarium has the proper bacteria in it to break down Ammonia->Nitrite->Nitrate. If your betta isn’t in a cycled aquarium this adds a lot of stress that could cause fin rot.
  • Heated Tank: Bettas are tropical fish! Betta fish naturally come from places where the temperature of the water is constantly in the upper range of 75-80 degrees F. This means that your aquarium tank should also be at that temperature range. This one action alone can make your betta fish really thrive in his environment. Most new betta fish keepers are told that betta fish can live in unheated glass bowls. While, yes I would agree that they can survive in these conditions. These fish will be so much more active and happy in a heated aquarium. 
  • Proper Diet:  Betta fish are carnivores, more specifically insectivores. In the wild, these fish consume various insects: ants, mosquito larvae, flies, worms to name a few. I don’t expect you to start hunting for insects in your backyard. However, what you could do is culture some easy insects for your bettas. Personally, I culture Grindal worms, Vinegar Eels & Brine shrimp for my bettas. I find these cultures are easy to maintain and my bettas are so much more lively when I switched from dry foods to live ones. Of course, if you really don’t want to have live insects in your house you can feed your bettas a mix of dry pellets, paste foods, and freeze-dried foods. A healthy mix of these foods will do wonders for your betta fish.


While betta fin rot might be common for many new fish owners, it can be completely preventable if you provide your betta fish with a proper home. While betta fin rot will destroy your betta’s fins, it’s also possible that your betta might be suffering from fin loss. This is not caused by a bacterial or fungal infection but rather something else in the tank such as a powerful filter flow, sharp decor, nippy fish to name a few. If you suspect that your betta is suffering from fin loss, find what object or fish that is causing the fin loss and remove it from the tank. 

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