Why do GoldFish Swim Sideways?

You must have fallen in love with your precious goldfish because of its beautiful appearance and attractive color. But what if you see your little one swimming sideways or upside down? Is your fish dead? There is nothing more terrifying than discovering your goldfish floating on its side. Well, they might be breathing this time. You can fix this issue and restore your jolly goldfish.

The reason why goldfish swim sideways is a disease named swim bladder disorder. The swim bladder of a fish gets affected by this disease. That is why they might float upside down, sideways, or might find difficulty in swimming back to the surface of the water. Severe illness can cause the death of your loved one.

You must be worried now. But hey, don’t give up. We’re here to ease your suffering.  Read more to learn more about the disease and the treatment for it.

What is ‘Swim bladder disorder’?

Swim bladder disorder is a widespread disease among fish, especially among the fancy goldfish (Red moor, Ranchu, Fantail), the betta fish, and koi fish. The swim bladder is an air-filled organ of the fish. It helps them to maintain their buoyancy.

The swim bladder gets affected by this disease, and the fish find it difficult to stay afloat. As a result, you may see them upside down or swimming sideways.

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What are the reasons for it?

The compaction of the swim bladder can cause swim bladder disease. It includes a bloated stomach from overeating, constipation, or gulping air, often when the fish eat floating food. The dried or flake food can cause swelling bellies when they expand after being wet.


The low temperature in your tank may slow down the digestive process of your goldfish, which may cause an enlarged stomach, causing swim bladder disorder.

Fatty liver, egg binding in female fish, or cysts can cause the swim bladder’s compression, causing the disease.

It is not likely for fish to have the disease from birth. But in some cases, you may find it.

Symptoms that your goldfish has swim bladder disorder:

The symptoms of swim bladder disease are quite similar regardless of whatever reasons. The most common symptoms include the awkward swimming of the goldfish. If your fish is affected by this disorder, you may find them swimming sideways. They generally float upside down and rise on the top of the tank giving you an impression that they are dead!

You may find them at the bottom of the tank facing difficulty while swimming upwards. They might appear with a swollen stomach if affected by swim bladder disease. Your fish might not have the appetite at all. They even may face difficulty in reaching the surface of the tank water and maintaining the normal position because of its disturbing buoyancy.


You’ve found out your fish is not dead. Congratulations!

Now what? Are you going to leave it like that? Absolutely not unless you want your precious one dead!

Follow the measures immediately to treat your fish.

  1. The swollen stomach or intestine is thought to be the reason for the disease. Keeping your fish fasted for three days would be the first and foremost duty of yours. If the condition is caused by a swollen belly due to overeating, you must keep your fish fasted for three days to ease them a little. Also, increase the water temperature to 70 -80 degrees Fahrenheit. The increased temperature often helps them to digest the food properly.
  2. After three days, you should provide them with cooked and skinned peas. You may boil or microwave them. Pea should neither be overcooked nor ripe. The pea may be dissolved in the tank water if it is overcooked. Be careful while cooking the pea. After cooking the pea, remove the skin while serving it. You should never give your fish more than one or two peas a day during the treatment. Continue this feeding habit for few days. Then, you may shift to its appropriate food. In the treatment period, avoid pellets and flakes that float.
    If any sort of infection causes the disorder, you might treat your pet with broad-spectrum antibiotics. You should visit the vet in that case.
  3. Reduce the water level of the tank for your fish to move about freely in the tank. Adding a small amount of aquarium salt may give you extra credit in this case. Keep the water flow of your tank to a minimal level. You might consider hand-feeding if your fish has a severe issue with swimming up to the surface.

Related:- How to Take Care of Your Koi Fish


They say prevention is better than cure. Well, now you must have understood the ultimate meaning of this particular proverb. Without further ado, let’s straight jump into the section where you might find suitable preventive methods for a swim bladder disorder.

  1. Since the swim bladder’s compression causes this disease, your first job is to feed your fish in a limited amount. Overfeeding may lead to a swollen stomach and intestines, causing the disorder.  Do not let your precious one gorge and gobble on food if you don’t want its discomfort.
  2. Many aquarists offer dried or frozen flakes or pellets as food. What you need to understand is that the frozen food gets extended or swollen after soaking. As a result, your fish overeats the dried food and faces difficulty. Often the fish gulps too much air while eating the floating food. Do not indulge yourself in offering it to them. Consider soaking the food before offering it because it helps the food to be submerged.
  3. Often the colder temperature leads to a weak digestion system causing a distended belly. Increase the temperature to 70-80 degrees Fahrenheit for healthy digestion. Do not increase the temperature too much if you don’t want to discover a boiled goldie in your tank!
  4. Offer high-quality food to your fish. Avoid the flakes that have air in them, causing air accumulation in your pets’ bodies.
    Consider giving them high-fiber food to avoid the issues regarding constipation.

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Final words:

With its fascinating fins and fancy tail, your goldfish can elevate the elegance of your aquarium only if it is healthy. Your responsibility should be providing the ultimate comfort when it comes to your pets.

Unfortunately, sometimes the goldfish do not respond to the treatment. Your only way there is euthanasia.

Don’t feel sad about it. We all have been on the same boat before. Do follow all the preventive methods to avoid all complications regarding the swim bladder disorder.

Your goldie is just like your own child, who needs care, comfort, and compassion. Understanding their pain and problems are the ultimate keys to save your loved ones. With the help of the methods mentioned above, you might be able to restore your pet’s health.

Get up and start treating your fish now to watch it in its full bloom again.

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