Why is My Goldfish Swimming Upside Down? 

Goldfish are happy fish with vibrant colors. They are active swimmers kept by both beginners and veterans fish keepers at home and in offices in an aquarium.

They are popular among people who travel a lot, because goldfish are believed to live for days without food.

However, imagine walking towards your aquarium one day only to find your goldfish upside down and floating on the aquarium? Upon careful observation, you realize the fish is not dead.

When a goldfish is swimming upside down it is suffering from buoyancy problems. This is a condition that does not only affect goldfish but also many any other species of fish especially betta fish.

Why is My Goldfish Swimming Upside Down? 

Why is My Goldfish Swimming Upside Down?

Buoyancy problems affects your fish swimming causing it to swim sideways or upside down. Buoyancy can be as a result of many factors, but most of them are related to poor health. However, you should not panic when you find your finned friend swimming upside down, because the condition is curable.

If your fish is swimming upside down, the most possible cause is swim bladder disease.  Swim bladder is an internal organ in a fish that is filled with gas. It regulates the fish’s buoyancy and ability to move up and down in water.

Therefore, when the swim bladder is affected it causes the fish to swim on its side, swim upside down and float on water. Although this condition is referred to as swim bladder disease, it is not a disease on its own, but a symptom of one of the several issues that could be affecting your goldfish’s swim bladder.

Causes of Swim Bladder Disease

Swim bladder disease can be caused by either temporary or permanent distortion of the swim bladder. When the swim bladder is affected, the fish loses its body stability while swimming. Deformation and narrowing of the swim bladder can be caused by a number of reasons;

Swallowing air

When feeding your fish, the fish may gulp in a lot of air as they try to grab the food that is floating on the surface of the aquarium. In addition, when you overfeed your fish, the fish may gulp in a lot of air to try to maintain its stability. Swallowing too much air affects the swim bladder.


Feeding your fish too much food, or feeding it poor quality goldfish food will cause your fish to have stomach upsets and constipation. Constipation, which causes blockage in the digestion cycle, can temporarily cause the fish to lose its ability to control their swim bladder.

Food expansion

Some types of food, for instance freeze dried food and dry pellets, enlarge when they get moist. Feeding your fish such type of food will cause bloating. A bloated stomach will press against the swim bladder causing buoyancy problems.

Bacterial infection

Swim bladder disease can also be a symptom of a bacterial infection. The bacteria could be affecting the swim bladder, causing the fish to problems in regulating its swim bladder.

Changes in the aquarium

Abrupt changes in the water can also lead to swim bladder disorder. For instance, changes in water temperatures can cause some variety of goldfish to develop swim bladder problems. High levels of nitrate in the water can also lead to swim bladder disorder.

Fancy goldfish, especially those with balloon like bodies, are more susceptible to swim balder issues.

Swim bladder disorders in goldfish are mainly caused by eating habits, eating too much or ingesting too much air while feeding. In that case, the condition fixes itself within a few days of fasting the fish.

However, if the fish portrays more symptom such as, a form of lethargy or discoloration in addition to lack of buoyancy, then it could be a bacterial infection and you should be concerned.

Treating Swim Bladder Disorder

Since swim bladder is caused by a number of factors, treating it will involve treating the factors causing it. Early diagnosis will also limit the damage caused to the swim bladder.

Before administering medication, it is advisable to move the goldfish to a different tank if it has tank mates.

Treating constipation that causes swim bladder disorder

Constipation is the main cause of swim bladder malfunction but also the easiest to treat. Constipation causes a stuffed stomach that presses against the swim bladder. A few days of fasting should restore your fish to normalcy.

However, a better approach is to feed the fish foods rich in fibre. The fibre will push out everything in the fish’s digestive system, allowing the stomach to go back to normal size and the fish bladder to function normally. To avoid future constipation problems, diversify the fish’s diet.

Watch the food that you feed your goldfish too. Avoid foods that expand when wet, these foods can cause constipation.

Treating swim bladder disorder caused by high levels of nitrate in water

Too much impurities in the water, especially nitrate, causes swim bladder disorder. Goldfish release too much waste compared to any other species of fish. The ammonia is converted to nitrite that causes swim bladder disorder.

If the swim bladder malfunction is caused by high levels of nitrate in the water, relocate your fish to a different water tank, and perform about 40% water changes in the aquarium to clean the water.

Treating bacterial swim bladder disorder

Bacteria can cause water accumulation in the swim bladder. However, water accumulation in the swim bladder can also be caused by poor water quality.

To determine the type of bacteria affecting the swim bladder, you need to perform an exercise known as pneumocentesis, which involves sticking a needle directly into the bladder. Once you are aware of the type of bacteria affecting the swim bladder, you are then able to administer the right antibiotic treatment.

Treating your goldfish with the wrong antibiotic will cause more harm. The best way to handle bacterial swim bladder infection is to seek advice from a fish vet.

Treating swim bladder disorder caused by physical injury or birth deformation

Most goldfish are as a result of selection breeding. As a result, some of the fish are born with swim bladder deformation. Physical injury may result from mechanical damage, for instance during transportation or conflict with other hostile fish species.

There is nothing much that can be done to treat a swim bladder that is deformed or physically injured. The best you can do is give the fish special treatment to ensure it leads a happy life.

How to Prevent Swim Bladder Disorder

Prevention is always better and easier than cure. To limit the chances of your fish developing swim bladder disorder, below are a few measures;

Avoid overfeeding

Fish do not understand the concept of overfeeding. They will definitely eat food offered to them. Overfeeding will cause constipation and a bloated stomach. Leftover food will also gather at the bottom of the tank leading to water pollution.

Create a feeding schedule for your goldfish. Feed the fish a pinch of its food two to three times in a day. The best way to determine if the food is enough is to feed it as much as the size of its eye.

Feed food that sink to the bottom of the tank

To ensure your fish does not gulp in too much air during feeding, avoid feeding him floating food, rather choose food that sinks to the bottom of the tank.

Soak the food before offering it to the fish

Dry pellets or freeze dried foods expand when they get moist. To avoid having them expand in the tummy of your fish, soak them in water before feeding.

In addition, frozen food gain volume when thawed. To avoid bloating caused by increased volume of the frozen food in the tummy of your fish, you can thaw it first before feeding.

Maintain stable water temperature

A fish’s metabolism is dependent on the water temperature. If the temperature is very low, the fish will digest food at a lower rate which may cause constipation. However, abrupt water changes can also cause your fish to develop swim bladder disorder.

Perform regular water changes

Changing the water in your aquarium regularly will limit the chances of the aquarium having high levels of nitrate which cause swim bladder infections.

Feed your fish a healthy balanced diet

Make sure your fish’s diet has all the necessary food nutrients it needs. If the fish is prone to suffer from constipation, make sure its food is rich in fibre.

Avoid balloon like fish

Fancy goldfish, especially those with a balloon like shape are more prone to suffer from swim bladder disorder. While picking out a pet, you can avoid these fancy goldfish species.

A goldfish that is swimming upside down is most probably suffering from swim bladder disorder. Swim bladder disorder may be caused by various issues, and it could also be a symptom of underlying health problems.

Swim bladder disorder is curable, and most times the issue goes away on its own. However, if the symptoms persist, it is important to seek advice from a professional veterinarian, who has experience in dealing with aquatic life.

Goldfish   Updated: October 17, 2019
avatar Hey, I'm Fabian, chief editor at Aquarium Nexus. I really enjoy the aquarium hobby and love sharing my experience with others. If you have any questions feel free to contact me or leave a comment below.

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