Fish Swim Bladder Disorders, Diseases, Treatment | Pet Fish Swim Bladder

What is a swim bladder?

Bony fish have a specialized organ called a swim bladder, whose purpose is to store oxygen and gases to maintain neutral buoyancy at the fish’s desired depth — think of it as a diver’s built-in buoyancy compensating device (BCD).

Fish can be classified into Physostomes and Physocristos depending on the type of swim bladder they have.

• Fish with swim bladders, known as proboscis fish, gulp air at the surface to fill their swim bladder, which then flows quickly into the swim bladder through a tube-like connection.

• In freshwater fish, special gas glands enable gases dissolved in the blood to fill the swim bladder and keep it gassed.

The swim bladder is surrounded by a tough outer membrane and lies just below the spinal cord within the body cavity.

As well as aiding in posture and swimming, some fish use their swim bladder to make and sense sound. This organ is crucial to the overall health of the fish, but it is not immune to disease or malfunction.

What causes swim bladder problems?

There are many factors that can cause swim bladder disorders, but one of the most overlooked factors is water quality.

Poor water quality can cause sudden and chronic stress to fish, which can disrupt normal bodily functions (homeostasis) and lead to buoyancy disorders. If your fish shows any buoyancy problems, you should immediately check the water quality and correct it if necessary.

What does swim bladder disorder look like?

Swim bladder disorders can be identified based on several different observations: Most fish should maintain neutral buoyancy in the water. When their swim bladders are floating, they can easily move up and down the water column. Neutral buoyancySwim bladder obstruction can cause a fish to be positively or negatively buoyant.

• Positively buoyant fish They will spend a lot of time at the top of the water column and will be unable to move downwards. They may also float in abnormal positions, such as upside down.

• Negatively buoyant fish They may be observed at the bottom of the tank and be unable to rise to the surface or move to the top of the water column. Fish with negative buoyancy disorders may also adopt abnormal postures.

How Veterinarians Diagnose Swim Bladder Disorders in Fish

If you do need to take your fish to the doctor, make sure the vet is experienced in treating aquatic animals. You can also use databases like this one to find an aquatic animal vet near you.

The best way for a veterinarian to evaluate the swim bladder is to perform an x-ray.

X-rays can show very clearly the position and size of the swim bladder. They can also tell if there is fluid in the swim bladder, which is not normal. As the disease progresses, the swim bladder may become misaligned, which can be easily seen on an x-ray.

Swimbladder disorders in various fish

Goldfish

Swim bladder disorders are common in goldfish due to their round body shape and (in some premium breeds) very curved spines, which makes them even more complicated because goldfish have an open connection between the esophagus and the swim bladder.

Diet can sometimes cause excess air to enter the GI tract when feeding. Switching to a sinking or neutrally buoyant diet may improve mild disorders by preventing excess air from entering the swim bladder tube.

However, dietary changes may not easily cure swim bladder disorders in goldfish, and it is always recommended that pet owners discuss their options with their veterinarian before trying buoyancy correction devices such as floaties or weights. Binding a foreign object to a fish’s body can have devastating effects on its skin and mucus production, so should only be done under the guidance of a veterinarian.

carp

Carp are also prone to swim bladder disorders.

Koi with spinal deformities or nerve damage may develop secondary changes to their swim bladder. The size and shape of the swim bladder slowly change over time to compensate for the reduced mobility of the fish. These changes can be permanent, allowing the reduced mobility of the koi to survive in their habitat.

Cichlid

Chicklids are another group of fish that are prone to swim bladder disorders, which can manifest in both positive and negative buoyancy. To determine the cause of the swim bladder abnormality, a similar diagnostic procedure to that described above should be used.

Swimbladder treatment

Depending on the cause, swim bladder disorder may be temporary or permanent. Steps to manage and treat this condition should be taken at home, and treatment will depend on how much the swim bladder disease affects your fish’s buoyancy.

Positively buoyant fish

For highly buoyant fish, it is important to keep the skin moist as parts of the fish’s body may be above the water surface for long periods of time.

Do not cover the top of the tank to keep the fish submerged, as this reduces the diffusion of oxygen. Ask your vet what to put on your fish’s skin to protect it from the air.

Negatively buoyant fish

Negative buoyancy disorder, i.e. fish lying on their side, belly or head for long periods near the bottom of the tank or pond, should be controlled with clean, non-abrasive substrates such as glass stones. It is very important to keep these tanks very clean.

Preventing Swimbladder Disorders

Buoyancy disorders in fish can be difficult to diagnose and may not have a permanent solution. If you have a fish that is starting to have trouble swimming, check the water quality first. Water quality is often overlooked in the case of swim bladder disorders. For fish with proboscises, try a sinking or neutrally buoyant food to prevent excess air from getting into the swim bladder.

If swimming problems persist, consult your local aquatic animal veterinarian and request an x-ray to evaluate the swim bladder. Once the problem has been diagnosed and discussed, work with your veterinarian to make a plan for your fish’s future.

Fish can live long, happy lives with swim bladder disorders, and all it takes is some modifications to the tank and care.