Common Betta Fish Diseases

If you’ve decided to get a pet, no matter what type, it becomes your responsibility. From how they live to what they eat, their hygiene, and everything else should be on top of your priority.

When it comes to pet fishes, people imagine that it’s really easy. It’s a tiny fish, what harm would it do is the mentality most people have in mind. But they don’t understand how hard it is to maintain it.

Betta fish is an excellent fish to keep as pets. They’re visually stunning to look at and elevate the aesthetic of your homes. And they’re quite intelligent and would perform tricks if you teach them. But there are a lot of possibilities that they can fall ill if you aren’t too careful.

Signs that your Betta Fish is ill

There are plenty of signs that suggest that your betta fish is ill. While these signs don’t always mean that the fish has fallen sick, but it’s always a good thing to be cautious.

Bacterial infections are the most common diseases that affect betta fishes. In fact, it is one of the most common causes in almost all fishes. It occurs due to a lack of tank maintenance. So, you can save your fish’s life from a lot of this illness just by maintaining a proper tank.

Your betta fish shows following symptoms if it falls sick:

  • Change in color
  • Inactive
  • Damaged/abnormal fins
  • Disinterested in eating
  • Constant rubbing of fins
  • Staying at the bottom of the tank more than often
  • Gasping for air more than often
  • Pale yellow puss
  • Swelling
  • Spots around mouth or head.

Common Betta Fish Diseases

Fin/Tail Rot


Fin rot in betta fishes is one of the most common diseases amongst betta fishes. Initially, it begins along the end of a betta fish’s fin. And eventually works its way up to the body. Fin rot is a bacterial infection that is easily curable if treated at the right time. However, when the fish does recover, it might not have the same vibrancy it used to have previously.


It is quite easy to figure out if your betta fish has fin rot. Their fins or tail is torn and they have inflamed rays. They also have a certain redness or blackening along the edge of the tail or fins. You’ll also notice receding edges of the fin or blood line on the tip.


The most prominent cause of the fin/tail rot is because of a poor water condition. It is a bacterial infection and the bacteria that causes it is always present in water but inactive. But when the water in the tank gets dirty, it sort of awakes the bacteria and it turns into a deadly form.

Another cause of the fin rot is when betta fishes fight with other fishes in the tank. They pick on the fin that might cause injury. And if not treated in time, it causes the fin or the tail to rot.


Betta fishes won’t even suffer from fin/tail rot if you keep the tank clean. And you can easily save them if they do get it by, you guessed it, cleaning the tank if they’re in the early stage.

You can apply 50% Mercurochrome in the affected area with a cotton swab. You can also add almond leaf to the water after cleaning as it provides natural betta antibiotic. But if the fish has crossed the early stage, you need to treat them with medical antibiotic.


Constipation is another common disease that betta fishes suffer from. And it is also easily curable. However, if you don’t treat it right away, it might lead them to death as well.


When betta fish suffers from constipation, it becomes obvious from how they look. They have a swollen stomach, they become inactive and won’t eat their food. Their faeces either remains attached to them or, they’re unable to pass it through.


The most common cause of constipation in betta fish is overfeeding the fish. Their tiny bodies can’t digest a lot of food so it causes them to constipate.

Constipation also occurs due to feeding the wrong type of food. If you don’t feed them balanced food, it causes constipation.


The most common treatment for constipation is making your betta fish fast for a day or two. It allows faeces to pass through easily.

If that doesn’t work, you can feed them tiny amount of cooked pea or daphnia. The fiber in it will allow the faeces to pass.


Ich/ick, also known as white spot is one of the most common disease a betta fish could get. It is a parasite infection that occurs in the fish.


The betta fish start to get tiny white spots all around its body which are actually cysts. The cysts harbor the immature stage of the parasite and infect the fish.


Ich is caused by a parasite called ichthyopthirius. It uses the fish as a host. It multiplies as it falls off on the bottom and sticks to other fishes as well. Frozen live food can also cause ich.


The only way to get rid of the parasite is by removing the carbon filter, adding an ick treatment to the water, and raising the temperature to 85 degrees Fahrenheit. The cysts detach from the body and burst.



Another parasitic disease that is common in the betta fish community is velvet. This parasite looks like velvet, thus the name.


There are several symptoms of velvet in a betta fish. The fish looses appetite when suffering from velvet. They have a golden/copper colored dust-like appearance. And they’re regularly scratching their bodies against the tank.


A parasite named adult Oodinium attaches themselves to the body of the betta fish. It then creates a hard shell around themselves as they feed off the fish’s skin.


If you keep lights in the tank, turn them off in order to treat your betta fish. Increase the temperature of the tank up to 30 degrees to let the parasite die naturally. Make sure to clean out the tank and replace it with clean water. Also use commercial malachite green remedy to the affected fish.

Betta Fish Fungal Infection

Another common disease among betta fishes is the fungal infection. It is something that a lot of betta fishes suffer from in their lifetimes.


When suffering from fungal infection, betta fish tend to have cotton-like growth on their bodies. They become lethargic and lose interest in eating. And the color starts to fade and become pale.


This contagious infection is caused when a growth occurs in areas where slime/mucus coating is damaged. It mostly occurs in previously damaged regions.


The fungal infection can be treated by using spot treatment. Use 50% Mercurochrome in affected areas with a cotton swab. Make sure to change the water frequently. And always use the same dose of medication on a daily basis until the fungus is gone.

Swim Bladder Disease

Swim bladder disease is not as common in adult betta fishes as it is in the younger ones. They’re not infectious, yet dangerous if not treated in time.


When suffering from the swim bladder disease, betta fishes have difficulty swimming. They tend to swim only the sides and are unable to swim upwards.

They have a loss of balance and their swimming seems abnormal. You can also see the swollen abdomen in betta fishes.


The swim bladder disease is mostly caused due to overfeeding or poor water conditions. It also occurs due to bacterial infection caused by previous injuries from either fights or transportation.

Swim bladder disease can also be genetic in most cases. And in females, it occurs as a result of damage while mating.


Usually, the swim bladder disease heals itself in most betta fish cases. However, if it doesn’t, there are remedies available. You can make your betta fast for at least two days if it is caused by overfeeding. If not, use the Maracyn II antibiotic as suggested by the vet.



Popeye is strange disease that betta fishes suffer from. It is a result of bacterial infection that makes betta fish’s eye pop, but not in a good way.


When betta fish suffers from popeye, one or both of their eyes tend to swell. It also looks like the eyes are protruding from the socket.


The most common cause of popeye disease is poor water conditions. Prolonged exposure to poor quality water is the biggest risk factor. Tuberculosis also causes popeye in betta fishes.


The most important thing to do is keep the tank and the water clean. Change the water frequently, regularly for at least few days. Add a tablespoon of aquarium salt per ten liters of water.

You can also treat it with antibiotics like Maracyn II or Kanaplex.

External Parasites

External parasites in betta fish is a parasitic creature that lives on the outside of the fish. It is fairly common in a community tank for betta fish to suffer from external parasite.


Betta fishes suffering from external parasite tends to have darting motions. They also keep scratching their bodies.


The primary cause of external parasite is new fish or other aquarium creature that you introduce into the tank for the first time.


To avoid external parasite, make sure you put the new specimen in quarantine before introducing it to the tank.

If betta fish still manages to catch the parasite, make sure to clean the tank and change the water completely and add aquarium salt. You can also use anti-parasitic medicines like Tetra Parasite Guard.

Mouth Fungus

Mouth fungus is also known as Columnaris or Cotton Wool. It is a common bacterial fungus that is both good and bad for your betta fish. The fungus is already present in the water and can only turn deadly under certain conditions.


It is quite hard to track this disease as it doesn’t often shows a lot of symptoms. But if betta fish suffers from Columnaris, it develops cotton-like growth around its mouth and fins. As the infection spreads, the fins wear out.


To make sure that you’ve completely gotten rid of the Columnaris, you need to clean the tank thoroughly. From the water to gravel, plant and everything else, clean them. Add aquarium salt once cleaned. And after it’s all done, use either antibiotic or copper sulfate to the clean tank.


Furunculosis is a chronic disease or a bacterial infection. Even though it is treatable, it can be fatal if not treated in time.


If a betta fish suffers from Furunculosis, it develops open red sores around the body. It also causes skin abscesses. And also develops ulcers around the red sores.


The primary cause of Furunculosis in betta fish is, like most of other diseases, bad water conditions. The fish gets bacterial infections due to poor water quality and leads to the disease.


Again, clean the tank if you see the furunculosis symptoms in your betta fish. Make sure the water condition is proper. And use antibiotics like Fungus Clear after the change.

Anchor Worm

Anchor worms aren’t actually anchor-shaped worms that sticks to the betta fish body. They’re a rare type of crustacean that attaches to the betta fish’s skin and burrows in.


Anchor worms are rather large, thus, easily spottable. The bettas have difficulty breating and show lethargic behavior. They’ll also develop red soreness or ulcers around the body. And they’ll constantly scratch against different surfaces when they get anchor worms.


The primary cause of anchor worm is introducing new species of fish or plants into the tank. It is very rare to occur in a tank itself because it mostly happens in outside ponds.


Before introducing a new fish make sure to keep it quarantined. You can easily pull out the anchor worm if you spot one in your betta fish. You can also add Potassium Permanganate and API General Cure in your tank. Make sure you change the water and add aquarium salt to it as well.

Hole in the Head

Hole in the head or Hexanitiasis is yet another parasitic infection that occurs in betta fishes. You can spot tiny hole on the betta fish’s forehead, that can turn dangerous if not treated.


Hole in the head disease is literally what the name means. You see the tiny hole of a size of a pinhead on the betta fish’s forehead which indicates that your fish has this disease.


The primary cause of the hole in the head disease is poor nutrition and water quality. It is caused by a parasite called Hexamita that migrates into the sensory pores of the fish’s head and causes the surrounding tissues to decay.


The most effective treatment of hexamitiasis is using metronidazole which is also known as Flagyl. And the beneficial approach is feeding medicated fish food to your bettas.

But when the fish is severely infected, they don’t usually eat. So, in such case you can use the medication to the water.

Betta Fish Tumors


Development of tumor in a betta fish is probably the most concerning situation. In almost all cases, it means that it is the end of a betta fish’s life. However, it’s not the end of the world. You can still cure your fish if you’re careful from the very beginning.


The biggest symptom of tumor in a betta fish is the presence of a lump in the body. The lump varies in size. And sometimes, you can’t even notice it if they’re internal tumor.

Apart from the obvious lump, betta fish also get inactive if they have tumor. They’ll have serious difficulty swimming and they stop eating.


In most cases, betta fishes are already inclined to getting a tumor. So, as a betta fish owner, you don’t need to feel as guilty.

However, other factors that you as an owner weren’t careful of might also lead your fish towards danger. Not maintaining proper water hygiene, feeding them poor quality food, and letting carcinogenic into the tank are some other causes.


Tumor, as mentioned is an indication that your betta fish’s life is coming to an end. Since there is no real cure for betta fish tumors, all you can do is provide the best care possible for your fish.

But if it looks like your fish is in a lot of pain, it’s better to let them go. So the best thing to do in this case is to euthanize them.

No Appetite

There are plenty of reasons why betta fish lose their appetite. And frankly speaking, it is a bit worrying as well. Most of the time they’re only lazying around and don’t feel like eating. But oftentimes, the case can be severe. What you need to do is keep track of their eating.

A loss of appetite might lead to serious infections and diseases in the future. So, make sure you have your eyes locked on their feeding habit.


There are many different reasons that leads to no appetite in a betta fish. From mere laziness to something severe, it can be anything. In some case, your fish might be fussy for some reason but will eat it with no issue after a while.

Sometimes they won’t understand that they’re being fed. It might happen if you introduce new food to your betta fish or if they’re new to tank. It can also be if you’re either feed too much food or if the food is frozen solid.

Another possible reason can be that you have a new fish and they’re new to the environment. Or, they’re having difficulty adjusting to the water temperature and the environment.

But many-a-time, it might be because they’re suffering from some sort of illness.


Dropsy is one of the rarest and most fatal diseases that your betta fish can suffer from. If your fish suffers from dropsy, it leads to kidney failure.


Betta fish shows a few concerning symptoms if they suffer from dropsy. They get bulging eyes and swollen bodies. Their faeces turn pale and string-like. And they develop pretty noticeable protruding scales.


There are multiple sources that causes dropsy in a betta fish. The swollen body is caused due to fluid retention within the fish. When harmful bacteria enters the tissue that leads to organ failure.

Other causes can be lack of nutrition, poor quality water, and irregular water temperature.


This is another fatal disease that has no possible cure. The only solution you have is to euthanize the fish so it doesn’t have to suffer.


The most important thing to learn is that if you want your betta fish to have a good and healthy life, you need to maintain the condition of its tank. Change the water as frequently as possible, feed them nutritious food, keep proper temperature, and make sure your betta fish is happy and thriving.

The key to a healthy betta fish is proper hygiene and it is in your hands as owners to take care of it.

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