Betta fish, also referred to as Siamese fighting fish are commonly kept as pets within one’s office or home. Within their 2-3 year lifespan, with a small handful living longer, as an owner you may notice that your Betta fish has fallen ill. If this is the case, the following complete guide on Betta fish illnesses and diseases from A-Z will help you pinpoint what is wrong with your Betta and the steps you should take to help your fish make a full recovery.

It is important to understand that if you believe that your Betta is ill, you have to be timely in attempting to work out what is wrong with it and provide treatment to give your fish the best chance of overcoming the illness. Betta fish enthusiasts often suggest one keeps a Betta medical cabinet stocked with general medications for common illnesses in preparation if your fish is unlucky enough to fall ill.

Signs that Your Betta Fish has Fallen Ill

Although some of the following signs and symptoms may not always mean that your fish is seriously ill or has contracted a disease, many of these are tell tale signs that your fish is ill. These symptoms are generalized and cover most Betta fish illnesses although each specific illness will have its own unique set of signs and symptoms.

  • Damaged or abnormal fins (holes or rips in fins often indicate a sick Betta fish)
  • Color change (a sick Betta fish’s normal color may be faded)
  • Disinterest in food over multiple days
  • Inactive or less active than usual
  • Tendency to stay at the bottom of the tank or oppositely gasping for air at the top of the tank
  • Spots that have appeared around your Betta’s head and mouth
  • Constant rubbing of fins along the side of the tank
  • Swelling of Betta fish
  • Enlarged eyes
  • Pale yellow puss
  • Difficulty swimming

Betta Fish Diseases and Treatment

In the following section I will cover an extensive range of Betta fish diseases, illnesses and treatment. It is important to examine and determine your Betta’s illness and treat as soon as possible because often times it will decide the fate of your fish. Each section has explanation on the cause, symptoms and treatment for the disease.

1) Bacterial Septicemia / Red Streaks

Bacterial septicemia is one of the less likely Betta fish illnesses caused by Pseudomonas or Streptococcus bacteria.

Cause

Bacterial septicemia is caused by Pseudomonas or Streptococcus.

Symptoms

Bloody read streaks that occur across the body and fins, bloated, gasping for air, ulcers, lethargic and loss of appetite.

Bacterial-Septicemia-betta-fish-disease

Treatment

This disease is best handled by a trained veterinarian who will medicate your Betta with an antibiotic in a quarantined tank.

2) Constipation

Due to their high protein diet with little fibre, constipation in Betta fish is common but also very curable. It is important to treat constipation as soon as possible to avoid more serious problems with your Betta.

Cause

Constipation is caused by one feeding their Betta too much food or the wrong type of food. Dried foods can lead to constipation as they swell inside the stomach opposed to live frozen food which can be easily digested.

Symptoms

Swollen stomach, faeces remain attached or oppositely, inability to pass faeces, disinterest in food and inactivity.

Treatment

If you believe that your Betta is constipated you should:

  • fast your fish for up to three days to allow all faeces to pass and then introduce live foods.
  • If unsuccessful you can give your Betta a small amount of daphnia which helps to reduce constipation or others recommend feeding them the tiniest piece of cooked pea.
  • Once your fish is passing faeces normally again it is important to cut down on the amount of food you were feeding him previously as this is a large contributing factor to Betta constipation.

3) Columnaris / Mouth Fungus

Columnaris often called mouth fungus, is a common bacterial infection that in particular affects fish that have already fallen for another illness or stress, such as a poor diet or unsatisfactory environment. To prevent this disease, maintain high water quality and disinfect all equipment before it enters the tank. Columnaris is highly contagious so it is vital you remove and incubate infected Betta fish.

This disease can be internal but more commonly is found externally on Betta fish. There is also a slow and a fast strain of this infection and depending on which one your Betta has it will determine how likely it is to overcome the illness.

Cause

Caused by the Saprolegnia species.

Symptoms

Cotton like growth around Betta’s mouth and white spots on mouth and fins. As this infection spreads, the Betta’s fins will become frayed. If the infection is internal, it can often show no symptoms at all making it hard to diagnose before it is too late.

Treatment

To ensure that you treat Columnaris you must first clean the bacterial infection from the entire tank including changing the water, vacuuming gravel and adding aquarium salt. Once you have cleaned the tank, you can treat with an antibiotic or copper sulfate.

4) Dropsy

Although dropsy is a rare disease and is fatal if contracted as it leads to kidney failure, it is important to know the signs and symptoms to ensure you isolate the fish you believe have this disease to keep other Bettas safe.

Cause

Caused from multiple sources when bacteria gets into the tissue of the fish resulting in organ failure. The noticeable bloating of this disease is caused by fluid retention within the fish. Poor water quality, stress when transporting, lack of nutrition, drop in water temperature and other aggressive fish contribute to ones Betta fish contracting this disease.

Symptoms

Bulging eyes, faeces become pale and string like, protruding scales are noticeable when viewing fish from above (makes the Betta look like a pine cone), swollen body, Betta becomes inactive and disinterested in food.

dropsy-disease-betta

Treatment

Unfortunately once the disease has progressed there is no known, reliable treatment for your Betta fish. It is recommended that your fish is euthanized so that it does not suffer further from this disease.

5) Fin / Tail Rot

Fin / Tail Rot is common in Betta fish and starts at the end of the fin and works its way towards the body in more progressive stages. If treated, the recovery rate is high although when fins and tails grow back they may not be as vibrant or long as they previously were.

Cause

Fin rot can be caused by two Bettas fighting but can also be caused by the water quality of the tank. The bacteria that can cause fin rot lays dormant in all tanks but becomes dangerous to your Bettas when the tank is dirty, over occupied, the fish becomes stressed or injured.

Symptoms

Torn fins, inflamed rays, blackening or redness along edge of fin or tail, blood on the tips of fins and receding fin edges.

fin-tail-rot-betta-diagram

fin-rot-tail-rot-betta-fish

Treatment

If the fin or tail rot is in the earlier stages then the tank can be cleaned and aquarium salt can be added. Once this is done treat the infected area with 50% Mercurochrome with a cotton swab. If the illness has progressed antibiotics will be needed. Almond leaf can be added to the water after it has been changed as these release a natural Betta antibiotic.

6) Fish Lice

Cause

Caused by a crustacean parasite that feeds and lays eggs on the Betta fish.

Symptoms

Ulcers, wounds and a round parasite attach to the skin.

fish-lice-betta-fish

Treatment

Using a pair of tweezers, gently remove the parasite from the Betta fish. If large wounds are left behind, use a cotton swab dab 50% Mercurochrome on affected area.

7) Fungus / Fungal Infections

Fungal infections are quite common among the Betta population.

Cause

Growths occur on previously damaged areas where mucus/slime coating has been damaged. Fungal infections are contagious.

Symptoms

Cotton looking growths on the body / fin of the Betta, pale in color, disinterest in food, lethargic.

fungal-infection-betta-fish

Treatment

Spot treatment using 50% Mercurochrome with a cotton swab onto the affected areas. Use same dose of medication daily and change water frequently until all fungus has gone.

8) Gill Parasites

Cause

Caused by Flukes

Symptoms

Struggle to breath properly, rubbing along the side of tank, glazed over eyes, loss of movement.

betta-fish-gill-parasite-disease-1

Treatment

This type of parasite is best dealt with by a veterinarian.

9) Ich / White Spot

One of the most common illnesses among Betta fish. Ich is present in the majority of fish tanks and aquariums although healthy Betta fish have natural immunity to it.

Cause

Caused by a parasite ((ichthyopthirius) that uses the Betta as its host. Once it falls off it multiplies in the bottom of the tank and these new parasites then live off other Betta fish. Ich can also be carried by frozen live food.

Symptoms

Small white dots on the body and fins and in some cases the eyes, clamped fins, rubbing on ornaments and side of tank and may become less active.

betta fish ich symptom

betta-fish-ich-illness

Treatment

Use formalin or malachite green to treat the entirety of the tank. If raising the temperature of your tank is an option, clean the tank and raise the temperature to 85 F/ up to 30 degrees Celsius. These parasites cannot handle the heat so within a few days your fish will make a full recovery.

10) Intestinal Parasites / Internal Parasites

These parasites live off any food that the Betta fish eats making them very lethargic and in a sense they are being starved. An owner must identify this early to treat the Betta fish in order for it to be successful.

Cause

Caused by parasites that often enter the tank through food such as brown worms. Intestinal parasites are much rarer than external parasites in Betta fish.

Symptoms

Change in behavior, lethargic and weight loss while eating normally. Intestinal parasites are contagious from one Betta to another.

intestinal-parasites-betta-fish

Treatment

Change out tank water and clean any object that are going back into the tank. Add one teaspoon of aquarium salt to the new water. If your fish does not improve after this, you will need to purchase antibiotics from specialized aquarium shops.

11) Popeye

Popeye is a bacterial infection which causes the Betta’s eye to swell and protrude from the socket.

Cause

Popeye is commonly caused by poor water quality from not enough water changes.

Symptoms

One or two of the Betta’s eyes will be swollen or protruding from the socket.

pop-eye-betta-fish

popeye-betta-fish-disease

Treatment

Popeye can usually be dealt with by changing the water for a few days in a row, and adding one teaspoon of aquarium salt per ten liters of water. If the swelling does not reduce you may need to purchase antibiotics.

12) Poisoning

Cause

Poisoning of your Betta is the direct result of an unsatisfactory tank leading to high levels of ammonia, nitrite and nitrate.

Symptoms

Betta fish who have been poisoned have a tendency to stay at the top of tank and gasp for air.

poisoning-betta-fish

Treatment

Test the levels of ammonia, nitrite and nitrate in the fish tank using an aquarium water test kit. Dispose of water and fill tank with clean water that has been treated with chlorine remover. Some suggest using bottled water for the tank because the levels of these things have already been previously tested.

13) Slime Disease

Slime disease is common and is caused by three different parasites. Slime disease also weakens the Bettas immune system which makes them more prone to getting a secondary illness or disease.

Cause

Caused by Costia, Cyclochaeta and Chilodonella parasites.

Symptoms

Frayed fins, grey/white coating on body of fish that looks like mucus, loss of appetite, inactive and cloudy eyes in some cases.

slime-disease-betta-fish

Treatment

Perform frequent daily water changes for up to a week and use malachite green. Also the use of aqua salt for up to ten days is recommended to cure slime disease.

14) Swim Bladder Disease

Not as common as other diseases in Betta fish, swim bladder disease is more common in younger Bettas . This illness is not infectious.

Cause

Caused by a bacterial infection that is usually the result of previous injury from transportation or fighting among Betta fish. Swim bladder disease can also be the result of overfeeding or poor water quality. Swim bladder in female Betta fish can be the result of damage during mating.

Symptoms

Difficulty and abnormalities when swimming, swimming on side, difficulty swimming upward, loss of balance when swimming and Bettas abdomen is swollen.

swim-bladder-disease-betta-fish

Treatment

Generally, a Betta fish will cure itself within a few days although to cure a Betta with swim bladder disease (that does not cure itself) one must administer an antibiotic. Also making the water shallower helps the Betta fish to breath and feed easier.

15) Tuberculosis

Cause

Tuberculosis in Betta fish is rare and your fish will become sick for no apparent reason. It progresses fast and you may not even realize that your fish has it until it passes away from the deadly disease.

Symptoms

Weight loss, open wounds, bent spine, fin and tail rot, other abnormalities. Be careful if you believe that your fish has TB as in some cases humans have contracted this deadly disease from a fish.

betta-fish-tuberculosis

Treatment

There is no known cure for Tuberculosis in Betta fish and generally they will not survive long once they have contracted it. It is recommended that you throw out anything that has come into contact with a Betta that has this disease due to the nature of how deadly and contagious it is.

16) Velvet

Velvet is common among Betta fish and comes in the form of a parasite that looks like velvet.

Cause

Caused by parasites (adult Oodinium) that attach themselves to the Betta fish. The parasites create a hard shell around themselves for up to a week while they feed off the Bettas skin cells. Once they release themselves from the Betta they multiple at the bottom of the fish tank and then reattach themselves in greater quantities to the Bettas in the tank.

Symptoms

Golden/copper colored dust like appearance on your Bettas body and fins (this can be easier to see with the use of a torch), clamped fins, scratching against tank wall and loss of appetite.

velvet-disease-betta-fish

Treatment

To treat a Betta who has velvet, turn off tank lights, and if possible increase the water temperature up to 30 degrees Celsius because the parasites cannot thrive in these conditions. Once this is done use commercial malachite green remedy. It is important to treat all fish in that tank due to velvet being so contagious. Make sure you also clean the tank and fill with new clean water.

Tips to Ensure Your Betta Fish Remains Happy and Healthy

Once you have diagnosed your Betta fish with a particular illness and medicated as needed there are a few things you can do regularly to ensure your fish stays happy and healthy. It is important to remember when housing a Betta fish prevention is always better than cure so we recommend you:

  • Clean your tank or fish bowl regularly
  • Check pH levels of the water
  • Quarantine new fish that you bring home
  • Add aquarium salt
  • Ensure you don’t overfeed your fish
  • Remove dead fish from a tank immediately for the safety of other fish in the tank
  • Ensure the water is warm

betta-fish-tank

Another helpful article to read on this topic is the betta fish symptom checker.

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Comments

  1. Marlene says:

    My little guy and I need help. He developed very mild fin rot over a month ago. There is too much conflicting advice. It’d be helpful for someone to say, if you add the salt in the proper amount it will show up between here and here on a hydrometer. My water is hard. Everyone says treated tap water is best, but if it’s that hard add. .. RO, distilled or spring to the mix, no more than 50%, treat as though tap water. RO killed my fiddlers. I was using distilled and tap for about a month, I was told stop right away, use spring. … I am so frustrated.
    I used salt for the first week, melafix for the second, back to salt. At first he was just staying the same all the time, then all of a sudden he had a spot on his dorsal, next day it was split. All the other spots only curled, never changed color, split or affected his behavior. I decided to go back to melafix. Then I read the ingredients! I read weeks ago that tea tree oil was only a preventive, not a cure. Now I’m seeing a lot of negative about melafix. I have ParaGuard, I haven’t tried yet. YouTube videos tout it as being great for fin rot, one betta site says it will not cure fin rot. The bottle claims it will. All this conflicting advice is making me nuts and him sicker. Up until today he has been very active. Every water change I mess up his bubble nest, right away he starts fixing it. Today he didn’t. I’m worried all this trying to make him well is making him worse. Just salt and frequent water changes kept it from getting worse, but not better, until yesterday. That dorsal fin really concerns me. What about dips, do you think that’s a good idea? With ParaGuard? He’d have to go into a 1/2 gallon container in his tank to keep him warm. Please give me some good advice, even if it’s where to find it. Frequent changes can’t be good for him. I have researched this very well, it’s just too much misinformation, or just conflicting, I don’t know where to turn. I actually saw a site that told people to wash their silk plants in SOAP and water. There was no place for me to leave a comment. Sorry so long. .. I’m just afraid I’ll wake up and he’ll be dead in the morning.

  2. Denise says:

    My Betta had all the signs of lethargy. I realized his water was cold so I bought a heater. His color is back and he’s swimming around more but he is still not eating. I changed diet from flakes to dried shrimp and blood worms. He puts food in mouth then spit out. It has been over 2 weeks that he’s not eating much. What else can I do?

    • Madison Davis says:

      He may simply not like that type of food. I know it can be a delicacy to some Bettas but surprisingly, a lot of mine don’t like this. Try the pellets. Everyone of my Bettas lod them.

    • Leona says:

      When I first purchased my betta from the pet store, he would not eat the flakes I bought. I went back to the pet store and asked what has he been eating, I bought the flakes they said and he still refused to eat. I bought some pellets, and he did the same with every food, tasted it and spit it back out. I started searching online for answers, I found a few and improvised my own. He hasn’t eaten for 2 weeks and I’m getting worried. Buy frozen peas, unthaw one, take skin off and cut into bite sized pieces, I was so happy, he just gulped it up, so he would eat peas, I then crushed the pellets up to very small pieces, took some blood-worms and coated them with the crushed up pellets (sort of ended up like a paste) and then tried to get him to eat it by hanging it at the end of a toothpick, it took a few tries with the consistency of the paste like, but he eventually started to eat the blood-worms and paste. I did this for maybe a week or two by slowly getting the paste thicker and thicker and then one day I just fed the pellets and he ate them. He had no issues eating after that, but he preferred the pellets and not the flakes. He still got the blood-worms as a treat.

  3. Ella says:

    My betta has been slightly bloated, hes quite lethargic, he hasn’t been eating, and his fins look all shredded for a few weeks. I have tried a few different treatments but his symptoms keep worsening. Can anybody offer any advice?

    • Wesley Smith says:

      Sorry to hear that Ella, to fix the bloated problem,first try a 3 day fast. That is when you don’t feed for 3 days in order to let it clean it self out. With the lethargic problem, make sure your water is between 75-80°F, cold water slows down their bodily functions, including eating, and passing wast. With the shredded fins, after your water temp is at 75-80°F feed foods with a main ingredient of krill, or something that is high in protein. *WHEN BUYING FOOD, CHECK THE PROTIEN, FIBER, FAT ANOUNTS. This is crucial for good health* to heal fins naturally, feed high protein foods at a steady amount. With time it will heal. *also make sure your decorations are silk and arnt sharp, this Could shred fins*

  4. Fin says:

    Ella, you should try using aquarium salt…that seems like a multi-purpose cure for a lot of diseases. You could also try fasting him for a day or two.
    My betta fish right now has some white-ish thing on the scales near his face. I don’t have a fish doctor near me. Should I try quarantining him with aquarium salt? Or is there something else that you recommend?
    Thank you so much

  5. Sol says:

    Hello, so I bought a male betta around four months ago. He’s always been small in comparison to others, however I don’t really think much of it. I currently have him in a five gallon heated and filtered tank, which I assume is the minimum, and haven’t had any issues besides minor fin rot since I have gotten him. He’s always been quite active and would constantly dart across his tank, however he was eating fine and appeared to be alright with no other concerns. I had to leave home for three weeks, so I gave both him and his tank to a friend of mine whom I trusted. He came back alive and well, however he is a lot less active and his colouring appears to have darkened. Is there anything that I can do/should check for?

  6. Iris says:

    My fish needs help! I just got him today from a pet store and he looked terrible so I wanted to help him! His small little plastic encloser had a green film coating the bottom and he had tail rot. He is a half moon male betta and doesn’t move or swim very often, it looks like his spine is bent and he primarily stays at the top of the tank semi resting on the side. What does he have? What can I do to help him? I know it’s only the first day but I am honestly worried! The ride home was also rough it was bumpy and icy.

  7. Kyler says:

    My fish, Mr Sparkes had a brown spot on the top of his head and was really inactive and wouldn’t eat. Then one day I went to feed him and he was on the bottom of the bowl dead

  8. Ally says:

    Although this was all very helpful and informative, I need some further assistance.

    My Betta shows symptoms that could be a number of the illnesses listed above. Today it looked like he started to gasp for air.

    He used to be all black/dark blue with small hints of red but, he started turning white with some hints of red.
    I think he could have:
    -Bacterial Septicemia / Red Streaks
    -Fungus / Fungal Infections
    -Tuberculosis

    I thought it was from when we cleaned the water in his tank last time, he got a little crazy and I think he scratched himself on the fish net. So I think thats where it started.

    I read online that it could be helpful to use Better Fix Remedy which, we have been using and it seemed to get better. But, now it looks like its going back to what it was. So looks like he is getting worse now.

    Not sure if there is something I can do to help treat him at home? I also read about trying this: MercuroChrome Antiseptic 1oz Prevent infection in cuts, scrapes and burns QTY-3, has anyone tried that before does it work?

    Thanks for any advice

  9. Alli bennet says:

    Recently I’ve noticed a small white dot on one of my fishes fins. It doesn’t really match anything on this list, and he still seems really healthy. It almost looks like a some of his food, but he’s been eating for nearly five months and I’ve never seen it there before. I’m really worried it might be something bad. Any ideas?

    • Alli bennet says:

      Recently I’ve noticed a small white dot on one of my fishes fins. It doesn’t really match anything on this list, and he still seems really healthy. It almost looks like a some of his food, but he’s been eating for nearly five months and I’ve never seen it there before. I’m really worried it might be something bad. Any ideas? I think it might be slime disease, and if so where can I buy treatment?

  10. Andy says:

    I got my betta fish almost two months ago. He’s been doing great but recently he’s been acting strange. He mostly has been laying at the bottom of the tank, changing spots periodically and occasionally going up to get air. He does not seem too interested in food and keeps his fins close to him now. He seems to have a few issues swimming and flinches and swims away from all the objects in his tank except for the bottom (he never did this before). I changed his water and he’s made a slight improvement but not much else. He has a 3 1/2 filtered tank and a heater and is by himself. Any help would be appreciated since I can’t really seem to identify his issues exactly with the ones above.

  11. Joanna says:

    My boy Orion has what looks like ich for 2 days now, but today part of his rays fell off where the ich-like stuff was. He’s a stubborn Crowntail and i absolutely cannot get him to flare. He’s been his usual active self, but one of his gills wont open fully. The people said it was from an old injury and i’ve had him for roughly 9 months with no issues but it’s still worrying. I’m not sure if he has ich or something worse. All of his water parameters are where they should be. He’s in a 10 gallon with a filter and heater and i feed him twice a day. I clean his tank once a week and do 25-50% water changes. He’s been in the same tank with the same decorations and plants since i got him and this is the first time he’s gotten sick.

  12. Aaron says:

    Hi!
    My three l333 pleco died yesterday, the symptom is redness spot on the side of theirs body and underneath the belly. I feel so sad, I couldn’t save them, don’t know how. Any help from you would appreciated.

  13. jasmine says:

    I currently have a 10 gallon with a betta, a neon tetra, and 3 corys. In the tank i have a heater and a filter and i do around a 20% water change every week. About a month ago i decided to change out the rocks so i carefully took them out and put the new ones in and then siphoned the tank once the water settled down. About a day after i noticed 5 of my neon tetras had died, so i removed them as quickly as possible and did another siphoning. After this happened I took a sample of my water to my local fish store, they told me everything was fine, except my pH was a bit off so they told me to buy some pH equalizer and a solution of good bacteria to add accordingly. Since then i’ve been adding the bacteria and pH balanced as directed and i’ve noticed all of my fish have become extremely inactive. the only time i notice them is when they swim up for air, my cory’s just lay at the bottom all day. I also noticed today that my betta has been only staying at the bottom of the tank and now has large scratches on him. He is acting as if he has swim bladder, but i wasn’t sure so i quarantined him in a container in shallow water so he can reach the surface of the water to get air, and i also added some aquarium salt to help with infection and stress coat. what should i do!?

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