Skip to main content

15 Common Betta Fish Diseases (With Pictures): Prevention and Treatment

Fredrick is a supplier of pet food and care products, and he’s a true animal lover. He loves to write about dogs, bettas, bees, and pigeons.

Betta fish suffer from a number of health conditions, but the good news for keepers of this fish is that these health problems can be prevented and also treated. If the infections occur in the aquarium, they can be easily identified and treated effectively.

This article covers all the common diseases and illnesses of betta fish, as well as their prevention, diagnosis, treatment, and cure. If you keep Siamese fighting fish at home, read on to learn how you can keep your aquatic pet healthy.

Betta fish diseases and illnesses can be categorized as fungal, parasitic, or bacterial. Most fungal infections result from previous health conditions. Parasitic ailments are the most contagious, and can be introduced into the aquarium by new fish. The most common causes of bacterial sicknesses include poor quality water and inappropriate fish handling methods.

The Common Diseases of Betta Fish, in Brief

  1. Fin and Tail Rot
  2. Columnaris
  3. Hemorrhagic
  4. Dropsy
  5. Pop Eye
  6. Eyecloud
  7. Mouth Fungus
  8. Furunculosis
  9. Fish Fungus
  10. Velvet
  11. Ich
  12. Anchor Worms
  13. Hole in the Head
  14. Swim Bladder Disorder
  15. Betta Tumors

1. Fin and Tail Rot

As the name suggests, this disease affects the fins and tails of betta fish. It can be caused by bacteria or fungi. The fins and tail appear to melt away or discolor as a result of rotting.

It can be prevented by keeping the aquarium or living conditions of the fish clean.

Fin and tail rot can be treated by medications containing antibiotics, such as trimethoprim, erythromycin and sulfadimidine.

If it is effectively treated, the fatality is medium.

If you have had fin and tail rot affecting your fish, you may have tried medications such as Tetracycline, Jungle Fungus Eliminator (JFE), Maracyn or Melafix. But the truth of the matter is that these medications are not quite effective in treating this infection, and some even kill your fish.

I have had little success with JFE and the other medications showed no success - they even worsened the condition. According to my own experience, the most effective medication for fin and tail rot is Hikari Revive manufactured by a reputable company.

The medication is itself a 5-day treatment, and it comes with clear instructions on how to use it. The most amazing thing about this treatment is that it starts to give positive results from day one! According to the manufacturer, it can also deal with pop eye, hemorrhagic septicemia, dropsy, open red sores, body slime, mouth fungus, cloudy eyes, and other many health conditions.

If you have the fin and tail rot disease or the related infections in your aquarium, I would encourage you to go for this medication. I have been using it since I discovered it in 2010 and I have had no disappointments with it.


Fin and tail rot

Fin and tail rot

Scroll to Continue

Read More From Pethelpful

2. Columnaris

This is a bacterial illness that causes the fins to rag and fray. It also causes skin ulcers or lesions, white spots or marks on the mouth, cottony growth on the mouth, scales and fins, and gills discoloration. The fish can have breathing difficulties as a result of the gill infection and damage.

The sickness can be prevented by treating open wounds and fungal infections. It can also be prevented by avoiding factors, such as limited oxygen, water hardness and overcrowding in the aquarium.

Columnaris can be treated by Oxytetracycline and antibiotics containing Sulfa 4 TMP, TMP Sulfa and triple sulfa.

If the infected fish is not treated, it can die in less than 72 hours.

Columnaris

Columnaris

3. Hemorrhagic

Commonly known as redmouth, hemorrhagic causes serious bleeding inside the mouth and eyes of the fish.

The disease can be prevented by disinfecting the aquarium to kill Yersinia ruckeri, which is the bacteria causing the illness.

The treatment of hemorrhagic is possible with antibiotics such as ampicillin.

The infection is treatable, which means that the fatality is low.

Hemorrhagic

Hemorrhagic

4. Dropsy

This is a deadly ailment that affects the kidneys. The infected fish can have swollen belly or abdomen as a result of accumulation of internal fluid.

Some more symptoms include; outward-sticking white scales and sunken eyes.

The bacterial infection can be prevented by keeping the aquarium clean. It can also be prevented by feeding fish with vitamins-rich foods.

There is no known cure for dropsy but medications, such as Betta Revive, can help with the condition.

Most fish that suffer from Dropsy do not survive.

Drospy

Drospy

5. Pop Eye

This disorder causes swelling on one or both eyes. The swelling can be a tumor or viral infection.

Pop eye is usually a symptom of a disease and can be avoided by preventing infections in the aquarium.

Antibiotics such as Tetracycline can cure the ailment.

Most fish that suffer from pop eye survive at the end.

Pop eye

Pop eye

6. Eyecloud

Commonly known as cloudy cornea, this disease causes white films on the eyes.

It can be prevented by improving the quality of water. A water conditioner is needed to make the water safer for the aquatic animal.

Eyecloud can be treated by antibiotics such as Metafix and Fungus Clear.

The bacterial sickness is not fatal but can impair vision.

Eye cloud

Eye cloud

7. Mouth Fungus

This is actually a bacterial disease, and it causes white lines or clumps around the lips and mouth of the fish.

It can be avoided by keeping the water clean, i.e., changing and conditioning it regularly.

Amoxicillin as an antibiotic can cure mouth fungus. Other medications that cure general fish fungus (described below) can also help with the infection.

The infected fish cannot survive if the illness is not treated early enough.

Mouth fungus

Mouth fungus

8. Furunculosis

The symptoms of furunculosis include skin ulcers and open red sores that can also appear on the fins and tail.

Improving water quality can effectively prevent the disease.

Fungus Clear as an antibiotic can treat this bacterial ailment.

Furunculosis can kill fish that doesn’t receive treatment in time.

Furunculosis

Furunculosis

9. Fish Fungus

This is a fungal disease that originates from previous infections. The affected betta usually has cotton-like growths, white fuzz films, slime (mucus-like discharge), or white lumps and bumps on the skin.

It can be prevented by avoiding primary infections and injuries and keeping the aquarium clean, i.e., changing and conditioning the water regularly.

Antibiotics such as Methylene Blue and Fungus Clear can cure fish fungus. It can also be treated effectively by the Bettafix Remedy mentioned below.

The sickness can become fatal if it is not treated early enough.

Fish fungus

Fish fungus

10. Velvet

Betta fish infected with velvet appear to have a rusty skin and scaly head including the gills and belly, and can also have black spots or marks allover the skin causing a color loss.

The parasitic disease can be prevented by improving the quality of water and ensuring the living conditions are stress-free. Water conditioners are some of the best substances to improve the living conditions.

It is highly contagious but it can be treated fully by API Body Cure. Manufactured by Aquarium Pharmaceuticals, this medication consists of curing components such as sodium chloride, copper sulfate, acriflavin, formalin, sulfa 4 TMP, methylene blue and malachite green.

With all these healing components, this remedy can also be used to treat all the other diseases, illnesses, sickness and disorders listed on this article. I have been keeping bettas for almost 15 years, and I have seen this medication heal my aquatic pets. I recommend that you use it to prevent, control and treat many ill-health conditions.

If velvet is not treated early enough, the infected fish dies in a matter of days.

11. Ich

Also known as white spot, ich or ick is a parasitic disease that causes white dots, rings, marks, or spots on the belly, fins, tail, gills, and other parts of the skin of betta.

It can be prevented by changing and conditioning the water regularly, and also optimizing parameters like ammonia, pH, nitrites, and dissolved solids.

The sickness can be treated by Fish-zole or salt bath, but I recommend Ich-X which provides great improvement within a week. According to my own experience, it is safe on plants and other useful organisms in the tank.

It is very easy to deal with the illness if treatment starts early.

Ich

Ich

12. Anchor Worms

This is a parasitic disease that attacks the tail or fins. The affected parts appear red and swollen and have protruding worms and threads of slime.

It can be prevented by treating any newly infected fish and keeping the water clean.

Some antibiotics such as Methylene Blue and Parasite Clear can cure the disease.

The ailment can become fatal if it is not treated early enough.

Anchor worms

Anchor worms

13. Hole in the Head

Betta infected with hole in the head have an abrasion on the head that looks like a pinhole or white fuzz.

The parasitic infection can be prevented by cleaning water off carbon.

Parasite Clear is an antibiotic that can cure the disease.

The infected fish usually dies after a few days if it is not treated early enough.

Hole in the head

Hole in the head

14. Swim Bladder Disorder

Also known as flipover, this disorder forces the fish to float at the surface of the water. The affected fish swims sideways or upside-down and can also lie at the bottom of tank. It is caused by constipation, poor water conditions, parasite or bacterial infections and enlarged organs.

It can be controlled by maintaining a high quality water, avoiding overstocking and feeding the fish with the right amount of fresh and fiber-rich foods.

When it comes to the treatment, the swim bladder disorder can be stopped by raising the water temperature, letting the fish fast for some days and then feeding them with cooked peas.

Fish with swim bladder disorder

Fish with swim bladder disorder

15. Betta Tumors

Betta tumors are usually cancer lumps, growths, or minor bumps/cysts under the skin of the fish. They mainly affect the reproductive organs, gills, tail, and abdomen, and are caused by genetic mutations and viral infections.

The tumors can be controlled by feeding the fish with healthy foods, maintaining a clean tank, treating other infections, and keeping carcinogenic substances away from the tank.

As far as treatment is concerned, the malignant tumors can be hard to cure, but some simple surgical operations can help. The benign tumors and cysts can be treated in a number of ways depending on the cause the lump or bump.

Betta with tumor at the tail

Betta with tumor at the tail

Summary

DiseaseTypePreventionTreatment

Fin and Tail Rot

Bacterial/Fungal

Clean living conditions

Tetracycline/Waterlife-Myxazin

Columnaris

Bacterial

Treat open woulds

Oxytetracycline

Hemorrhagic disease

Bacterial

Disinfect aquarium

Ampicillin

Dropsy

Bacterial

Keep aquarium clean

Betta Revive

Pop Eye

Bacterial

Control other diseases

Tetracycline

Eyecloud

Bacterial

Improve water quality

Metafix/Fungus Clear

Mouth Fungus

Bacterial

Improve water conditions

Amoxicillin

Furunculosis

Bacterial

Keep water clean

Fungus Clear

Fish Fungus

Fungal

Avoid primary infections

Methylene Blue/Fungus Clear

Velvet

Parasitic

Clean living conditions

Bettafix Remedy/Fish-zole

Ich

Parasitic

Change water regularly

Fish-zole/Malachite Green

Anchor Worms

Parasitic

Treat new fish

Methylene Blue/Parasite Clear

Hole in the Head

Parasitic

Avoid carbon in water

Parasite Clear

Swim Bladder Disorder

Disorder

Avoid overfeeding

Fasting/raise water temperature

Betta Tumors

Malignant/Benign

Give healthy foods

Surgery/viral medication

Conclusion

Now you have it. With this information, you can keep betta without any worries of their infections and illnesses. Some fish can develop behavioral conditions, such as stress, lethargy, and poor appetite, but you shouldn’t be worried about these short-lived conditions, especially if your fish is new in the aquarium.

Moreover, betta fish can suffer from fading color or abnormal color change, and can develop things like bubbles and solid particles like blobs on their bodies. These conditions can be controlled by changing and conditioning the water regularly, and also optimizing parameters like ammonia, pH, nitrites, nitrates, air, water hardness, water temperature, and organic matter and dissolved solids.

Important: If you haven't found a solution for your fish yet, do not fail to check the comments, questions, and answers below.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

Questions & Answers

Question: My betta has been hanging out at the bottom of the tank, she doesn’t really eat. Sometimes she’ll zip around the tank and then right back to the bottom. I tried betta fix. What else can I do ?

Answer: Well, you need to check other signs of sickness in her. If she lacks these signs, then she might not be sick. It is actually normal for fish to stay at the bottom or eat less/not to eat for a certain period.

Question: My betta fish is pale and is alive but at the bottom of its tank. What does it mean when a betta fish remains at the bottom of its tank?

Answer: Highly likely that you are overfeeding him and has developed the swim bladder condition. See how to deal with the condition from the article.

Question: My new Betta fish, that I got from Walmart (so you know it was in horrible conditions before I got it) is now gasping at the top of the water; he flares up anytime that anyone comes around him, he's not swimming like a normal Betta fish does either. He's my baby brother's fish, and he would be devastated if it were to die. What can I do to treat him?

Answer: It looks like you have fed him a lot, and as a result, has developed the swim bladder condition. See how to deal with the condition from the article. He could also be under stress because of the new conditions, so you can also wait to see if he'll get better.

Question: Why did my beta kill itself by butting its head onto the tank?

Answer: Didn't you see him/her butting? He/she could have developed an infection on the head.

Question: My betta fish is not moving much and is lazing around on one side of the tank. Its fins appear to have become stiff. What is the cause and cure for such a condition?

Answer: It looks like he's being overwhelmed by the conditions of the water. Try changing and conditioning the water, and maintain the right levels of water parameters - pH, ammonia, nitrites, etc. See all parameters in the comment section of this article.

Question: My betta fish is slow, sleeps at the bottom of the tank and doesn't move much. What could be wrong?

Answer: This is highly likely to be a swim bladder condition. See how to deal with it from the article.

Question: Should I feed my betta while medicating, or is it best to let her fast a few days during treatment?

Answer: There is no problem unless you are treating him of the swim bladder condition.

Question: Recently, my betta has been swimming with his body downward and head up or just staying like that at the bottom of the tank for long periods of time. Every time he tries to get to the top it is like he is having trouble swimming. Is there a possibility he could have gotten hurt somehow? We have had him over a year with no issue.

Answer: He could also be having the swim bladder condition. See the condition from the article.

Question: My fish has been lying at the bottom of his tank for 2 days now. His head seems to be discolored and a little swollen. He swims frantically every so often then just goes back to the bottom. Any idea what this problem with my Betta fish could be?

Answer: It's highly likely that the quality of the water has turned poor. You can try changing it regularly and optimizing parameters like pH, dissolved solids, ammonia, nitrites, etc.

Question: My dragon-scale betta has a tumor on his side. Is acting well, but it's getting bigger. Could I do anything special to help him?

Answer: It's usually not easy to deal with tumors, but you can consult a vet for some kind of a surgery.

Question: I recently got a beta fish from a friend whose kept it in awful conditions, it appears to have fin and tail rot and is incredibly lethargic. How might I help it? I want to try to save it the best I can.

Answer: You can keep him/her in a clean tank with well-conditioned water, and then treat the disease. See medications from the article.

Question: I recently got a red betta fish. After a few days I have noticed its scales started turning blueish-purple with black edges (?) and a bit of black edges were on his tail as well. Is this bad?

Answer: If he's old, it's normal - color can change with age. If it's young, then it's issues with water, and you can try changing and conditioning the water regularly plus optimizing parameters like pH, ammonia, dissolved solids, etc.

Question: My female Betta has a bump growing beneath her scales on her upper back. What could it be?

Answer: Most bumps on the dorsal area are usually tumors. It could be a tumor, but you need to monitor its progress as well as other symptoms.

Question: I have had my Half-moon Betta for about 3 years and most of that time he has been sick. Half of his head is covered in black. Furthermore, the black is now starting to spread and he has marks of black. Ever since I bought him, he has always had fin rot problems, even to the point of losing his whole back tail. I have cleaned the tank often, changed tank sizes, and used Bettafix but nothing helps. Is there any way to make him better?

Answer: You can try another medication - see Waterlife Myxazin for fin and tail rot. Also, you need to check and optimize water parameters such as dissolved solids, pH, ammonia, nitrites, etc which are well known to affect the skin color.

Question: My betta fish can't eat anything. He always spits it out, tries again and then gets tired of trying. When he tries to chew his gills go in and out. Whats wrong with him?

Answer: The food could be hard and he's trying to soften it. Other possible reasons include overfeeding, bad food that he doesn't like, sickness or mouth ulcers/lesions/cavity.

Question: Why at the beginning do you say tetracycline doesn’t work, to use Myxozin, and on your list at the end you say treatment is Tetracycline?

Answer: It is not quite effective, as it is written, but I have seen it work for some selected cases. The disease seems to have developed resistance for the compound which is found in a number of drugs. Myxazin is now included in the table in the latest edit.

Question: My betta is losing his color in his tail fin. His bottom fin has turned red... HELP ME PLEASE! What should I do?

Answer: You need to change the water regularly, keep the entire tank clean and maintain the right levels of water parameters - pH, ammonia, nitrites, etc. See all the parameters in the comment section of this article.

Question: My betta fish has three small raised white spots on one side of her gills. I treated for ick several times and didn’t work. Tried amoxicillin several times and didn’t work. I have changed and treated the water several times and still no changes. Even tried aquarium salt. The white spots look like they are coming out of the gills. What could this be and what should I try next?

Answer: Most white spots are usually fungal, and you can just try another medication. See the Bettafix Remedy mentioned in the article.

Question: Do you have any comments on a beta with only one eye? it's not clouded or hoping, it's missing completely. he came like this and I'm trying to see if he needs any extra measures, like maybe he could be more susceptible to infection? is it common for a beta to develop only one eye?

Answer: That's likely to be a birth defect, and I think it doesn't affect his health. If there is an opening around the missing eye or it's a damaged eye, then infections can occur, and therefore you need to always keep the water clean.

Question: My Female Betta has been lying at the bottom and top of the tank; not moving for a few minutes at a time. Her fins are never open, and she often spits out or sort of vomits her food when she eats. Her abdominal looks white and a bit large, but we always thought it was her babies. Do you happen to know if anything is wrong with her?

Answer: You could be giving her food that causes digestive issues like bloat. You can try changing the food to see if there are any positive changes.

Question: My Betta fish has little orange spots on its eye and side. And its been staying at the bottom of the tank ever since I changed the water. What do I do?

Answer: It looks like he's being overwhelmed by the conditions of the fresh water. You need to check if the source of water is safe, and also check if the water parameters are in their right levels. High levels of parameters like ammonia, nitrites, pH, chlorine, dissolved solids, temperature, etc. can cause some issues including spots. See all the parameters in the comment section of this article.

Question: My fish have pop eye and eye cloud, and after giving some medication antibiotics now it's having some other problems such as velvet, and there is a white spot near its fin. How do I treat it?

Answer: Get the Bettafix remedy under the velvet section (from the article) to deal with the two diseases.

Question: my Betta cannot move her body except for her two little fron