What is swim bladder disease in aquarium fish? How to Prevent it?

If your fish doesn’t seem to know whether it wants to sink or float, it may be suffering from a swim bladder disease, or floating disease. Japanese fishermen called this disease of floating tenpuku, which means capsized. A very appropriate name for the poor fish’s condition. The swim bladder is an organ in bony fish, like goldfish and Betta. This gas-filled organ mainly helps fish float, as well as hear and communicate, so damage to this organ can be life-threatening.

Some fish are born with a malformed swim bladder. An example of this is fancy goldfish. Their body shape often leads to the disease. Other fish develop the disease through digestive problems such as how or what they eat. These issues revolve around trapped gas interfering with the fish’s ability to float. 

Often pet owner habits can be changed to avoid the disease. Some diseases that have nothing to do with the swim bladder have an impact on the functioning of the organ. Infections, cysts, and parasites can all damage the organ indirectly.

Finally, trauma for many reasons can also cause the swim bladder to malfunction. This includes rough handling or other aggressive fish. This can also happen if a fish gets dropped on the ground during tank cleaning or moving. 

As a fish owner, cleaning your tank and feeding your fish appropriately are the most effective ways to prevent swim bladder disorder.


How To Prevent Swim-Bladder Disease?

Although in some instances, swim bladder disease is unavoidable in a fish, many times it is caused by a fish owner’s habits. Keeping your tank clean and healthy should be a priority to avoid many diseases. Poor tank conditions obviously lead to infections, and many of these infections end up causing swim bladder disease.

So how do you maintain a clean healthy freshwater aquarium? Make sure to check the water regularly for ammonia, nitrite, nitrate, pH, and hardness. Smaller tanks will need at least a third of their water changed on a consistent basis or as needed to remain clean. And be sure to check your filter for clogs, but never rinse them away with tap water because this kills good bacteria. You can also add some aquarium salt to your tank.

Another way to keep your tank clean is to feed your fish smaller amounts more often throughout the day. That way extra food doesn’t dirty the tank, and fish aren’t tempted to overeat, which can cause a variety of complications.

What you feed your fish as well as the way you feed your fish is also important in their health. If you’re using dried pellets or food, try adding a drop or two of moisture to it first. Buying a high quality food that has more moisture in it, such as gels or live food, can help fish with digestion. Using food that sinks into the water quickly, rather than food that forces the fish to eat at the top also helps stop them from sucking in air while they eat.

What Are The Signs And Symptoms of Swim-Bladder Disease?

A beautiful, healthy fish will move with grace and speed through the water, reminding us of a mythical mermaid or a daring dolphin miniaturized. An unhealthy fish looks more like a beached whale in its own aquarium.

Although the most common sign of a swim bladder disease is your fish floating upside down, a swim bladder disorder can be tough to spot if you are not a fish expert. Besides your fish floating like he’s dead, other signs he may be suffering from a swim bladder disease could include sinking to the bottom, floating along the top or on his side, or the inability to control his movement in the water. Often, fish with swim bladder disorders will swim with their head lower than their tail. Basically, if your fish isn’t swimming normally, a swim bladder disorder could be the cause.

The anatomy of your fish may also change, cluing you in to the disease. Physical signs of this could be a belly that is sticking out or a deformed back. If the case is severe enough, the fish may not be able to eat, although sometimes appetite is not affected. A fish that gets stuck on the bottom of an aquarium generally has more luck eating than one stuck floating at the top.

Since fish breeds are different, one way to see if your fish is acting normally is to watch some videos of healthy fish of the same breed. You could also talk to pet store workers, other fish owners, online groups, or your vet if you’re that unsure. X-rays are the most effective way to see if your fish has this disease.

What Causes Swim-Bladder Disease?

There have not been many studies done on swim bladder disease, and those that have been done didn’t find consistent results. Since fish are such delicate and sensitive creatures, there are a number of reasons one could have a swim bladder disorder.

Their own genetics can occasionally be the cause of a malformed swim bladder. Fancy-bred goldfish and other short-bodied fish can have an unnatural shape to their internal organs because of specialized breeding.  Internal cysts can also disfigure the swim bladder, causing discomfort and the inability to swim correctly.

Poor water quality in the aquarium can cause the swim bladder to overwork.  A sudden drop in water temperature also forces the organ to work harder than normal.

Lack of proper nutrition or cheap food can also lead to numerous issues. Digestive trouble and complications are also common causes of swim bladder disease.

All of these are outside factors that cause damage to the actual organ. Too much air in the swim bladder makes it so a fish can’t control its floating. The organ actually being moved around inside the fish’s body may impact its ability to control its swimming. If a fish gets fluid in the organ, it cannot swim to the top. Gas in or around the bladder affects the fish’s swimming control. In the worst case scenario, an actual rupture of the swim bladder would cause death because it couldn’t be repaired. All of these internal causes of the disease are painful and uncomfortable, as well as nearly impossible to cure in some instances.  

Do you need to worry about the other fish in your aquarium catching swim bladder disease? No, because swim bladder disease actually refers to many issues that could stem from the swim bladder’s damage. It is a physical abnormality that affects the quality of life for that individual fish. 

Treatment For Swim-Bladder Disease

Although swim bladder disease is generally treatable, many times fish perish because of the external damage to their bodies. This can happen while they are pressed against the bottom of the tank or stuck floating on top. If they can’t control their floating movements, they’re basically a ship in a storm without an anchor or sail. In order to save your fish if possible, you may have to try several strategies.

Making the fish fast for several days is suggested to support clearing out digestive issues. Some evidence suggests after fasting, feeding the fish a green pea, soft and skinned, to help. If your fish has too much trouble moving, you may have to hand feed it.

Controlling and changing the environment your fish lives in is another way to improve chances against swim bladder disease. Adding sodium chloride to the water permanently may help with your fish’s balance. Adjusting the water temperature, level, and flow are also ways to help your fish get better.

If improving the environment for your fish’s condition isn’t enough, there are medicines. Many times a swim bladder disease is caused by an underlying disease. Different medications tend to treat different infections which have hurt the swim bladder.  With the quick treatment of these diseases, hopefully surgery does not become necessary. There are also floatation devices that can be attached to fish for short periods of time to help them recover. Sadly if it gets to the point where your fish is suffering or there is no improvement, putting it down is often the best option for it.

Swim-Bladder Disease in Various Fish

The anatomy of the fish breed plays heavily into the risk of the fish getting swim bladder disease. There are some fish that don’t have a swim bladder, or whose swim bladder is so reduced it is not worth mentioning. These tend to be bottom-dwellers or sharks.

Although nearly any type of fish with a swim bladder can get the disease, goldfish and Betta are the most common types of fish to have swim bladder. This is because of their body shape and eating habits. They have a curved spine already, and their esophagus and swim bladder have an open connection. They also eat at the top of the tank, making it more likely they’ll gulp in air.

Koi develop the disease because of their large size and breeding practices. Cichlids are also prone to this disease because they go through specialized breeding, which can cause changes to their bodies. Despite the susceptibility of certain fish to swim bladder injury, nearly any species of fish can develop the disorder.


The swim bladder in fish compares to lungs in humans, according to Charles Darwin. So when you’re looking at that beautiful aquarium full of healthy fish, remember that we aren’t so different from them after all. Just as health is important in humans, a fish’s health should be important to a fish owner.

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