Betta Fish Open Wound – Why Does This Happen?

Physical harm to animals is nothing new. Novice aquarists could mistakenly believe that fish in a controlled ecosystem known as a tank is safe from physical damage. 

Even though fish seem to inhabit a secure ecosystem, there are many other potential threats to their health than you think.

In today’s article, we will talk about the betta fish’s open wound, the physical harm that bettas frequently suffer, and the damage to different portions of their bodies when living in aquariums.

What Is Open Wound (Ulcer)?

“Ulcer” refers to an open wound in the fish’s skin that may expose the muscle layer beneath to your naked eyes. Internal organs may be visible through abdominal sores, and fish deaths are more likely to happen due to severe damage.

Numerous factors, such as trauma or a parasite, might cause ulcers to become traumatized.

Open Wound on betta

As a result of the aquarium’s design, bacteria are constantly found in the water and may manifest themselves on the fish’s skin. 

Your betta fish are prone to developing an ulcer if the bacterial infection overwhelms its immune system or if they encounter a particularly unpleasant bacterium strain. 

Your fish may initially float on top, but once the germs have eaten up the outer layer, they may succumb to sepsis or bacterial overgrowth.

Invading germs are typically kept away from fish’s outer skin layers by the mucus layer on its body. So, it is crucial to retain the mucus in fish because it contains many immune-boosting components.

Betta Fish Open Wound – Why Does This Happen?

Betta Fish

Some common reasons that cause the open wound in Betta fish can be noticed:


Fish can develop hostility toward prey, their home range, and breeding grounds. The use of force can take the form of charging, stabbing, butting, and chasing. 

More docile creatures may become stressed just by expecting an assault. Stress and an open wound from an injury can foster the growth of bacteria-filled sores.

Fish Fight

It is conceivable that certain dwellers in a school of fish with a varied assortment may be warier than others and vice versa. 

With no rhyme or reason, violent fish like the Betta, Tiger Barb or Red Tail Shark engage in fights with other fish. 

However, some timid fish, including Koi or Marble, prefer a peaceful existence. Shy fish frequently suffer injuries when aggressive fish begin to attack them without cause.

Decor Items

We all enjoy adding various decorations to the aquarium to make it appear more appealing. 

Driftwood, artificial corals, colorful stones, and sculptures are a few of the typical ornaments found in fish tanks. Even though they are in good shape with no jagged corners initially, these products tend to enlarge somewhat over time and endanger fish. 

So, you must be aware of the tank ornaments and periodically check them to determine whether they have any jagged or rough edges.


You might have to move your Betta fish from one aquarium to another if you’re a new aquarist and occasionally replace the water or examine the tank. The scales will still peel off, and the membrane of the tail is ripped regardless of whether you use a net to pursue them.

Also, fish injuries can result from rubbing against the aquarium’s rocks and walls as people chase them around the tank. 

Unsuccessful Predation

Although we typically believe that fish don’t eat one another, keep in mind that they are opportunistic. Even the softer species can swallow the small fish in the tank if food is scarce. 

Little fish attempt to flee, so if the hunt usually happens, they will suffer.


Although fish are excellent swimmers, they frequently collide with tank walls, ornaments, pebbles, and other objects. 

Even though such accidents do not result in death, they might still result in some anomalies or deformities in various bodily areas.

Too forceful impacts can harm the body’s interior organs. The impact is frequently responsible for the swelling around the head or the mouth of betta fish.


Inappropriate substrate use frequently results in abrasion. There will be times your betta will lay on the bottom of the tank, so you need to use a substrate that won’t affect them because the creatures that live at the bottom will suffer from sharp sand and abrasive gravel.

How To Treat Wounded Betta Fish?

If the accident happens, there are some actions you need to do to treat your fish.


Quarantining your fish in a separate tank is the primary thing you should do if you see any of them wounded. 

The fish will experience a less stressful environment in the new place where there are no other fish or danger that can harm them, and the wounds will recover much more quickly. 

To stop additional infections, you can also put prescribed treatments, like antibiotics, in the water.


Start your therapy with clean water if your fish has a bodily injury or an open wound. It would help if you moderated the degree of water every day until the injury starts to recover and the fins start to regrow. 

Besides, you can use specific lotions with tea trees to support the mucous layer and aid healing.

While waiting for the Betta’s defensive system to take control, the best treatment is fresh water and one of the disinfectants above. Keep checking fish every day for infections, paying special attention to signs like:

  • The fin’s tip is black or bloody 
  • Fins break off
  • Ripped and shredded fin tip
  • Red streaks or an unnatural amount of bodily redness.
  • The body, jaws, or fins have translucent blotches or filaments.
  • Open wounds that enlarge, spread, or alter colors 
  • An additional infection like Popeye, Velvet, or Ich

Consider applying antibiotic therapy if there are infection symptoms. Ich and velvet are parasites that usually attack stressed-out fish with vulnerable immune systems. Antiparasitic medicine ought to be taken if there are symptoms of sickness. And remember to keep the water consistent, warm, and hygienic.

The Bottom Line

Betta fish open wounds can occur for a lot of reasons. It will become fatal to your fish if you don’t treat it immediately or appropriately. 

Hopefully, this post has served you with a lot of useful information. Thank you for your time. See you around!