Betta Fish Ulcer – Everything You Need to Know

Freshwater fish ulcers are a prevalent issue. When a fish’s defenses are compromised by a primary stressor, such as a parasite harming the skin and enabling germs to enter, ulcers are most frequently the result.

A few crucial elements may be checked to manage simple ulcers, but severe ones may need veterinarian attention.

What Are “Betta Fish Ulcers”?

A skin lesion that causes tissue necrosis is known as an ulcer. Betta may be injured by a variety of initiating events, including parasites or trauma.

The underlying musculature may be exposed as a result of severe ulceration. Internal organs may be seen if an abdominal ulcer develops. Fish mortality is more likely to occur in cases of deeper ulcers.

betta fish ulcers

Because of the nature of aquariums, germs may grow on fish’s skin and are always present in the water. The body’s mucus layer and a fish’s immune system often prevent bacterial intruders from getting beyond the fish’s outer skin layers.

Because fish skin mucus contains many immune-boosting components, it is crucial to leave it on the fish. Polyvinylpyrrolidone (PVP)-containing water conditioners could make the slime coat better and help to heal the fish’s wound.

Your Betta is likely to get ulcers if the bacterial assault overwhelms their immune system or if you come upon a particularly unpleasant bacterium.

Your fish may be vulnerable to a full systemic illness or sepsis if bacteria have penetrated the outer wall, even though they may begin on the surface.

Signs of Ulcers in Betta Fish

  • Heightened scales
  • Increased vein redness (erythema)
  • Sizing loss
  • Red marks (varying sizes)
  • Skin breakdown
  • Exposing the muscles underneath
  • Reduction in the fin structure
  • Lethargy
  • A diminished appetite

Signs of Ulcers in Betta Fish

Causes of Ulcers in Betta Fish

Primary ulcerating bacterial infections in fish are uncommon. A common bacterium species will frequently exploit a decline in your fish’s immune system.

Fish benefit from acute stress reactions, which are linked to the “fight or flight” response. Chronic stress is the effect of a stressor that cannot be avoided.

Reduced immunological response, lower fecundity, and deteriorated physical state are the outcomes of chronic stress. Some of the most typical stressors for Betta fish include, but are not limited to, the following:

Poor Water Quality

The health of the Betta fish is closely tied to the quality of the water they swim in.

Ulcers are one of the numerous secondary ailments that can develop if your filtration system isn’t kept up and you ignore bad water quality. Additionally, Betta fish housed in colder water will have a less robust immune system.


Betta fish parasites can put them under stress and destroy their skin, which makes it easier for germs to get into their bodies. When a Betta fish has parasites on its skin, it frequently “flashes.”

Flashing is a habit in which fish scrape themselves using their substrate and any decoration, revealing a brighter belly that resembles a flash of light.

This action may resemble “uncoordinated swimming” or “twitchy dancing.” When new Betta fish are put in an aquarium without being quarantined, parasites frequently infiltrate.

Remember that the temperature of the water in your aquarium will affect how quickly parasites finish their life cycle. The parasite’s life cycle must be entirely disrupted for the treatment to be effective. In outdoor ponds with fluctuating seasonal temperatures, this is crucial.

Poor Nutrition

Don’t only choose the most costly food container to provide your Betta fish with the optimum nutrients.

Do your research to determine the ideal diet for your fish. Does it consume plants, meat, or both? Choose the appropriate diet for the fish in your aquarium.

Your Betta fish’s immune system will decline due to poor or insufficient feeding. Giving your fish a variety of meals can reduce the possibility of nutritional deficits that might arise from eating the same item consistently.

Food shouldn’t be stored for more than six months since beyond that time it starts to lose too many of its vitamins. Keep your food in a pantry or cabinet in a sealed, light-proof container.

Keep the food inside, where the temperature is steady, for pond fish. The food will stay fresher for a longer period of time if you store it in the fridge or freezer.


Betta Fish can become violent while competing for food, a mate, or a territory. Charging, nipping, ramming, and pursuing are all forms of aggression.

Even the anticipation of an assault can be stressful for more docile species. Stress and open wounds from previous attacks might foster the growth of bacterial ulcers.

Treatment of Ulcers in Betta Fish

If the cut is minimal and the water conditions are ideal once a major stressor has been found and eliminated, your Betta fish will probably recover on its own.

Veterinarian care is necessary for severe ulcers, frequently involving antibiotic medication.

To determine the main bacteria of concern and a list of the antibiotics it is most sensitive to, your veterinarian may advise a bacterial culture and an antibiotic sensitivity test.

Your veterinarian may even recommend an antibiotic fish meal or administer an antibiotic injection to the fish.

Do not use over-the-counter antibiotics to treat the sores on your Betta fish.

The potency and effectiveness of these unlawful products are not examined. A dose that is not high enough to completely eradicate the bacterium may even cause the bacteria to develop antibiotic resistance.

Your biological filter will be destroyed by water-based antibiotic treatments, which will also put you under more stress.

How to Prevent Ulcers in Betta Fish?

It is crucial to reduce stress in your aquarium if you want to avoid Betta fish ulcers. If you are, then it is quite unlikely that a fatal bacterium would enter your aquarium.

  • Preserving good water quality
  • Carrying out routine filter maintenance
  • Providing a suitable
  • Fresh diet
  • Following the right biosecurity procedures
  • Properly quarantining new fish.


How can I tell if my Betta fish has an ulcer?

If you notice any redness, swelling, or discharge on your Betta fish’s body, it may be an ulcer. If the ulcer is large, it may cause your Betta fish to stop eating or become less active.

How can I treat a Betta fish ulcer?

If you suspect your Betta fish has an ulcer, take it to the vet for a diagnosis and treatment. The vet may prescribe antibiotics or surgery to treat the ulcer.

Can Betta fish ulcers be prevented?

There is no sure way to prevent Betta fish ulcers, but you can help reduce your fish’s risk by keeping its tank clean and free of debris.

You should also avoid overfeeding your Betta fish, as this can lead to obesity, which increases the risk of developing an ulcer.

Final Thoughts

If you have a betta and it develops an ulcer, it’s essential to implement the treatment right away.

There are a few different ways to do this, so be sure to talk to your veterinarian about the best option for your pet.

Ulcers can often be cured if treated early enough, but untreated fish can be dead. So keep an eye on your betta and remember that preventing fish ulcer is always better than curing it.