Is Swim Bladder Disease Fatal?

Is Swim Bladder Disease Fatal?

If you find your fish moving oddly about the tank, either stuck at the bottom, or the top, or even upside down, your fish has swim bladder disease. Now, before you get worried, this condition is very common in bettas, and there are several ways to treat it. Most of the time, you will have to make a change in the way you feed your fish and/or what you feed your fish, but other than that, there are normally no long-term consequences.

Swim bladder disease, also known as swim bladder disorder, is not a fatal condition in aquariums. In the wild, it could cause the death of fish because a fish will not be able to compete for food, but in aquariums, there is no need to. While it is possible for swim bladder disease to cause other health issues, it will not kill captive fish directly.

In this article, we will discuss swim bladder disease, common betta causes, uncommon betta causes, treatment, and prognosis.

Swim Bladder Disease

The swim bladder is an internal organ that allows fish to control its placement in the water column. Unlike humans, who only have to deal with forwards, backwards, right, and left movements, fish have to constantly control their vertical movements as well.

The swim bladder controls these movements through its use of air. If a fish wants to move upwards in the water column, they take more gas into their swim bladder. On the other hand, if they want to move down, they release gas from the swim bladder.

If this organ becomes damaged, the fish no longer has control over its placement in the water column. This results in one of three possibilities. The first is that the fish is stuck at the bottom of the tank, and when it tries to swim up, it appears that something is dragging it back down. This is referred to as negative buoyancy disorder.

The second option is the reverse of the first. Your fish may become stuck at the top of the aquarium and may be unable to move downwards. The third possibility is a fish that has delayed reactions, so it will randomly float upwards far more than it should, then overcorrect and float lower than it should, etc.

Even though issues with the swim bladder are commonly referred to as “swim bladder disease”, it is most commonly a “swim bladder disorder” and not a disease at all.

Common Betta Causes

For bettas, the most common cause is constipation. If the betta is unable to pass waste, all sorts of things can become displaced on the interior of the fish, and if the swim bladder is pressed, squeezed, or moved, it will not work properly.

Other causes include trauma to the swim bladder or infections, normally parasitic or bacterial. Since constipation is the most common cause, you should first examine your betta’s diet and how much you are feeding your fish.

The stomach of betta is roughly the size of its eye, so you should only feed an amount of food the size of its eye per meal. You should feed two meals for your betta every day.

In order to make sure you are feeding the right amount of food, put the food you feed your betta in a bowl of water and wait ten minutes. The food will swell, sometimes quite significantly. Base the amount you feed your betta on the swollen food’s size, not the dry size.

You should also ensure that your betta is getting enough fiber in its diet. Feeding supplemental food, such as frozen daphnia, is essential to keeping your fish healthy. Supplemental foods, such as frozen bloodworms, blackworms, white worms, and brine shrimp, provide extra nutrition and minerals for your fish.

Betta fish are carnivorous, so the best source of fiber for them has frozen daphnia. A good alternative is part of a deshelled blanched pea, but because this is plant-based fiber, it should not be fed on a regular basis.

Uncommon Betta Causes

If your fish is new, or you added other fish, invertebrates, and/or plants to your betta’s aquarium without quarantining, your fish may contract a bacterial or parasitic infection. In addition, the presence of any ammonia or nitrite, or nitrates over 20ppm, can also lead to bacterial infections.

If the cause is a bacterial infection, you will need a very strong bacterial medication to treat it, as weaker bacterial medications, such as Melafix, only treat external infections (sorry to all you Canadian fish keepers, you may have issues getting strong antibiotics from now on).

Erythromycin is a good medication for this ailment, but the specific brand does not matter, as long as it states that it can treat internal bacterial infections. The same goes for a suspected parasite, the medication must treat internal parasites, not external ones.

On the other hand, if you have a water quality issue, the only way to fix that is to do water changes. If your tank is not cycled, it will be very difficult to determine the cause of the betta’s distress, as ammonia, nitrite, and nitrate poisoning throws in conflicting symptoms, making diagnosis difficult, if not impossible. Infections caused by bad water quality are normally weak enough that the fish’s immune system can fight them off once the water quality improves.


The most common cause of swim bladder disease in bettas is constipation. This is easily treatable and does not cause long term damage. The treatment for swim bladder disease and bloat are the same, since the cause is often the same as well.

The first step in treating your fish is to fast the fish for three days. If the issue is caused by constipation, you don’t want to make it worse by feeding your fish more and more food that it cannot pass.

After the three days, you need to get either peas or frozen daphnia. The peas cannot have any additives, preservatives, or flavorings, as these can be damaging to fish, and they should be uncooked. Before feeding a pea to your betta, you should take off the shell and blanch it.

On the morning of the fourth day, feed your betta a small amount of either frozen daphnia or the pea. You may feed the same food to your betta in small amounts for a lunch and dinner meal as well.

If the first round did not help resolve the issue, feed your betta its normal food for a second and third day, then repeat the fasting and feeding. If there is still no improvement, you should consider other potential causes, primarily a bacterial infection.


Most of the time, swim bladder disease is treatable. However, if the cause of the disorder is trauma to the organ or old age, it is unlikely to be treatable, but it is not necessarily fatal.

For the most part, swim bladder disease is not fatal in of itself. However, it could get to a severe enough point where euthanization is the kindest option.

If your fish is unable to swim and can hardly move, that is not the best life to be living. That being said, euthanization is not necessary, as long as your fish is still able to eat.

However, if your fish is fully unable to move and stuck sideways on the bottom and cannot find food by his or herself, euthanization should be considered as an option. The only time that euthanization is definitively the best option is if the fish is floating upside down and has not responded to fasting or antibiotics.

This is an issue because part of the fish will end up out of the water. The part stuck out of the water will dry and crack, causing extreme pain. In this case, it is likely that the progression of the illness is too severe, and since the betta is in pain, the prognosis is very poor.

In conclusion, swim bladder disease is not normally fatal. The most common cause is constipation, which is a treatable issue. There are several other possible causes, but most of these are also treatable, though they are more intensive than the constipation treatment.

Leave a Comment