“Swim bladder disease” is one of the most common problems affecting goldfish. If you’ve seen your fish swimming upside down, or on its side, then you’ve seen a swim bladder problem.

Although often called a “disease”, it is actually a symptom that can have a number of different causes. There is not one specific “disease” that is the cause of all swim bladder problems in goldfish.

As it is not actually a disease, swim bladder problems are not contagious. If one fish has a problem, your other fish won’t “catch it”. However, they may still be at risk of developing similar problems.

Fortunately, swim bladder problems can usually be cured fairly easily, as long as you spot them early enough. If you see your fish swimming upside or on its side, act quickly!

There are several good swim bladder treatments available. But, before you try to cure your fish, read on to find out more about treating swim bladder problems.

What is swim bladder disease?

Swim bladder disease is when a fish loses its ability to regulate the air going in and out of its swim bladder. This causes the fish to swim strangely, on its side, or even upside down.

The job of the swim bladder is to help the goldfish stay stable in the water and control the way in which it floats.

If the goldfish wants to swim upwards, towards the top of the tank, then it will take air into its swim bladder. This makes the goldfish more buoyant (like an inflatable in a swimming pool) and it rises towards the surface.

If the goldfish then wants to swim downwards, towards the bottom of the tank, it will release air from the swim bladder. You may see this air coming out of the fish’s mouth in the form of bubbles as it swims to a lower point in the tank.

Fish swimming upside down

If your fish is swimming upside down, it has a problem with its swim bladder.

Your fish has stopped being able to control its swim bladder and has got stuck with too much air inside it.

The reason for this could be constipation, a poor diet, eating habits, or an infection.

Causes of swim bladder disease

Causes of swim bladder problems include:

Constipation, which results in excess food pressing against the swim bladder. This is a common problem in goldfish, which you can read about here.

Swallowing air at the surface of the tank when eating

Eating the wrong kinds of food, which then ferment in the gut

Sudden changes in temperature

Bacterial infection

Parasitic infection

Fancy goldfish often suffer from deformed swim bladders, as they have been bred to have such unusual body shapes.

Treating the problem in 5 easy steps

Swim bladder problems can be very serious. But there is hope! It is also one of the most straightforward issues to treat.

Follow these 5 simple steps:

Test the water quality and temperature. Is the tank properly cycled? Do you do regular water changes? Is there ammonia or nitrite in the water? Is the temperature stable? If not, you need to urgently take action to improve and stabilise your water parameters. Do not feed the fish for at least 48 hours. Don’t worry – goldfish really don’t need to eat much! After 48 hours, start to feed the fish very small amounts of peas with the shells removed. Add some aquarium salt (one teaspoon per gallon) to de-stress the fish. Try a swim bladder treatment. Try a treatment for bacterial infection.

You should soon see your goldfish start to swim in a more stable, upright position.

Stopping it happening again

After your fish has recovered from swim bladder disease, you should consider making changes to their diet.

Here are 5 top tips to prevent swim bladder problems.

Read our article on feeding goldfish and feed a varied diet to your fish.

Feed sinking pellets instead of flakes. You can find out more about pellets in our guide to feeding pellets to your goldfish.

Feed your goldfish peas with the shells removed, boiled vegetables, bloodworms and brine shrimp.

Soak food in tank water for a few seconds before adding to the tank. This will make sure it sinks and stop your goldfish gulping air at the surface.

Feed less regularly. Goldfish really don’t need to eat much at all. There is much more risk of over-feeding your goldfish than there is of under-feeding them.

Fish-keeper’s toolkit

We recommend having the following items in store to help prevent and treat Swim Bladder Disease: