Betta Fish Care

Betta Fish Diseases & Illnesses

Diseases in Betta fish are quite common. Sometimes the cause is genetics, and most often inappropriate care and condition in the aquarium. Unfortunately, despite the many warnings and the internet where it is possible to read all about Betta fish – the owners are still mostly irresponsible.

Like it or not, Betta fish require a large aquarium, careful care, and selected food. This is quite enough as prevention not to all, but most of the diseases that Betta fish can get.

Before we start with the presentation of the most common diseases of Betta fish, here is a little reminder of what it takes to properly care for and maintain the health of Betta fish:

  • Large aquarium (3 gallons per Betta fish)
  • filter, heater, and thermostat that work
  • Water temperature is constantly between 78 and 81 degrees Fahrenheit.
  • Suitable plants with soft leaves and rounded edges;
  • Decorations, shells, double hearts, and stones made of soft material that will not hurt the Betta fish.
  • Regular water change (approximately 20% every week)
  • Clean excess food from the aquarium after each meal
  • Regularly check the water for the amount of ammonia, nitrate and measure the Ph value.
  • Feed Betta fish with a variety of foods; not only flakes or pellets but also frozen and live food.
  • Don’t overdo it with food.
  • Observe and inspect the betta fish once a week to see if there are any changes or abnormalities in the body.

If you follow these rules, your Betta fish will have no problems. Prevention works wonders and if you are not ready to take care of Betta fish responsibly, don’t buy it. It is not humane for even one living being to be in bad conditions that only cause suffering.

Find out below the most common Betta fish diseases, symptoms, and treatment.

Fin Rot Disease

Diseases are caused by fungi, bacteria, and viruses and Betta fish can come in contact with them in different ways.

Fin rot is probably the most common disease of Betta fish due to poor aquarium hygiene. It is caused by fungi and bacteria and if it is not noticed in time – it is difficult to cure. As its name suggests, it is manifested by the rot of fins, which gradually spreads to the tail and other organs.

The symptoms are frayed and cracked fins, and often fall off. Open wounds and red or white purulent sores appear first on the fins and in later stages along the entire fish body.

Treatment usually consists of quarantine (placing the fish in a quarantine aquarium) and antibiotics. The most commonly used antibiotics are based on trimethoprim, erythromycin, and sulfadimidine. Some also suggest using aquarium salt and adjusting the diet of Betta fish.

What you should do is to make sure that the diseased fish are placed in a quarantine aquarium and that the main tank is thoroughly cleaned. Be sure to consult a specialist or veterinarian.


Velvet is a parasitic disease. Like most illnesses, it can be prevented by proper hygiene and regular inspection of the correctness of equipment such as a heater, thermostat, and filter. When this disease affects the Betta fish, its skin changes color and appearance; it becomes scaly and dark red, like the color of rust, and dark spots appear all over Beta’s body.

The disease is very contagious, so if Betta has roommates in the aquarium – be sure to transfer it to the hospital aquarium and clean the main one. Velvet can be treated by medicine containing sodium chloride, copper sulfate, acriflavine, formalin, sulfa 4 TMP, methylene blue, and malachite green.

As with most diseases – the success of the treatment depends on whether you have detected the disease on time and the strength of Betta’s immune system.


It is caused by bacteria and is manifested by red and white lesions on the skin, especially around the mouth; the skin becomes scaly and the fins flutter similarly to fin rot. The biggest problem arises when the disease affects the lungs and thus disables or makes it difficult for the Betta fish to breathe.

This disease is often caused by problems with oxygen and poor quality water. The filters may not work properly so the water is too hard or you may be pouring inadequate water into the aquarium. Remember that the water for Betta fish must be oxygenated, and this will be best provided by quality filler.

The infection can also occur due to a small aquarium or too many fish in it, where it is difficult to control all the conditions. It is mainly treated with oxytetracycline and antibiotics containing Sulfa 4 TMP, TMP Sulfa, and triple sulfa. The sooner you spot the disease, the better the chances that Betta will recover. Otherwise, it dies approximately 72 hours after infection.


This is also one of the most common Betta fish illnesses. It is caused by a parasite and when Betta’s body is infected, it becomes full of various spots and spots all over. In a way, Ich is a mirror of the owner’s responsibility.

So, if you regularly check water parameters such as temperature, nitrate, and ammonia levels – they can be very easily avoided. Fortunately, this disease is mostly curable and in easy cases, a mild salt bath and aquarium salt are enough. Severe cases require specialized treatment with antibiotics or other medications.

Swim Bladder Disease

It can be said that floating bladder disease is a set of several different conditions that are not treated in time. Often, prolonged constipation combined with polluted water and the inability of Betta fish to breathe – results in swimming bladder disease.

It can also be caused by bacteria and fungi. It is manifested by swelling of one or more parts of Betta’s body. This makes it impossible to swim, so Betta either floats or gets stuck somewhere at the bottom of the aquarium.

If Betty has not started to bend its spine and there is no twisting of the body – the disease can be treated by increasing the water temperature, fasting for one or more days, and a light diet that will regulate the fish’s digestion.


Dropsy is a somewhat outdated medical term for a disease now called edema (ascites). Unfortunately, this disease is in most cases difficult to cure and Betta fish often dies. It is caused by bacteria that are always present in a smaller or larger amount in the aquarium.

If Betta or any other species of fish became infected and developed dropsy – the immunity was weak or even never developed enough. Dropsy is characterized by the accumulation of water and swelling of the internal organs of the fish.

It attacks the kidneys, which prevents regular urination. Often white scales appear on the skin, Betta loses color and the eyes look as if they have shrunk or pulled into the body. The condition is difficult to cure but can be prevented by maintaining an aquarium and a nutritionally rich diet. Food must contain proteins and minerals and must not be monotonous and based on carbohydrates and fats. It often happens that if one fish in the aquarium get sick from dropsy, the others will soon. Since Dropsy is incurable and can kill an entire fish society in a very short time – proper aquarium hygiene and a variety of food are all you can do.

The diagnosis is sometimes complicated by ambiguous symptoms because almost all Betta fish diseases have very similar symptoms.


Yes, Betta fish can get tumors, but that happens very rarely. For the most part, Betta gets sick from diseases caused by fungi or bacteria. The tumor in Betta fish can be manifested externally, on the skin, fins, and tail, and can also be manifested on internal organs.

Sometimes internal tumors grow, so they look like subcutaneous pimples. All tumors generally look like protrusions and arise due to the abnormal growth of cancerous cells. Depending on the location – the growth doesn’t have to significantly complicate the life of Betta fish, at least not in the early stages.

There are also so-called white tumors, which are a kind of benign tumors, without cancerous cells. There are more growths, i.e. ulcers caused by infection with bacteria or fungi.

There is no cure for the tumor in Betta fish. Some develop more slowly, so your fish live longer and without much pain or problems. However, tumors of the internal organs will most likely spread over time and endanger the quality of life of the Betta fish.

Tumors are mostly genetic in Betta fish. They sometimes occur as a combination of genes and poor living conditions and frequent, poorly treated infections.


Unfortunately, often the symptoms of the disease in Betta fish are similar to most diseases. Sometimes, even more, diseases that occur on the principle of dominoes are combined. They are difficult to diagnose accurately and will often require the help of an experienced veterinarian. What you can do, however, is to be as responsible as possible and to provide your pet with the best possible living conditions.