Goldfish Swims Sideways

A goldfish is a tiny and cute thing, and quite easy to maintain too. However, they are also living beings and prone to health issues if you don’t care for them properly. 

Sometimes, the goldfish may get infections or sustain injuries despite the care. Changes in swimming patterns are a cause of concern and should be investigated thoroughly. 

If you notice your little goldfish swimming sideways, it most likely indicates an issue with the bladder. A goldfish with a bladder injury or disorder will swim sideways or upside down. You need to immediately take care of your sick goldfish, as your pet must be in pain. 

Swim bladder disorder is the most common reason for a goldfish to swim sideways or upside down. A few other reasons include an external or internal injury, old age, or weakness due to diseases and infections. Ammonia poisoning can also cause a goldfish to swim sideways.

But why does a goldfish get swim bladder disease, and how do you cure it before the condition gets even worse? How can you prevent swim bladder disease in your goldfish? 

Let’s find out in this blog. 

Swim Bladder Disorder in Goldfish

The goldfish swims forward, like most other fish. However, when its swim bladder is affected, the goldfish will be swimming upside down or sideways. 

The swim bladder is a gas-filled internal organ that allows the goldfish to make continuous movements in the water. It ensures that the fish can swim without wasting too much energy. 

When this bladder is disrupted or injured, it changes the goldfish’s movements. The swim bladder disorder is painful for goldfish. Ignoring it can lead to the death of the poor fish. 

Medical research articles show that up to 85% of fish with buoyancy disorder (swimming sideways or upside down) suffer from swim bladder disorder.  

Though it is called swim bladder disease, the condition is not really a disease. It is a symptom of different causes that affect the swim bladder of a goldfish and mess up its buoyancy. 

Fancy goldfish, such as the ones with bulbous heads and bodies, are more prone to suffering from swim bladder disorder. This is because the fish have limited space in the coelomic cavities and have only one swim bladder instead of two (which normal goldfish would have). 

Moreover, physostomous fish like koi and goldfish consume air when they eat food from the water’s surface. Since they already inflate their swim bladders through the pneumatic duct, additional air makes them bloated and leads to swim bladder disorder.

Getting it diagnosed at the earliest lets a vet treat it at the earliest. And that is why it is important to know the signs and symptoms and the risk factors for your goldfish developing swim bladder disorder.

Goldfish Swims

Ways to Identify Swim Bladder Disease in Goldfish 

Your fancy goldfish will exhibit the following signs if it is suffering from swim bladder disease:

  • Not eating its food properly 
  • Goldfish swimming upside down 
  • Swimming sideways in strange patterns 
  • Irregular or erratic swimming movements 
  • Swimming upward to the surface and back into the water repeatedly 
  • A swollen belly 
  • Swimming at the bottom of the fish tank 
  • Swimming with its head close to the bottom of the tank 

What May Have Caused Swim Bladder Disorder?

Bladder Disorder in Your Goldfish

Swim bladder disease is caused by many reasons. Knowing the root cause will help you find the best solution to treat the problem and save your goldfish’s life. Here are the possible causes of SBD:

Bacterial Infection 

The goldfish’s swim bladder can be affected by bacterial and fungal infections caused by poor water quality in the fish tank. Aquarium fish are sensitive and need proper hygiene to survive in confined spaces. 


The fish’s stomach is tiny and can be hurt by excess food. The round body of goldfish makes them more prone to constipation. The digestive system is delicate and can be affected by overeating or even if the goldfish swallows air more than necessary.

This puts pressure on the swim bladder and affects their movements. Bloating is another reason for buoyancy problems in goldfish and results in sideways swimming. 

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Physical Injury or Strain 

Aggressive fish will attack and butt into your little fish on the sides. This can hurt the goldfish’s bladder, leading to a swim bladder disorder. Such incidents happen when you introduce a goldfish into aquariums with fish that feel territorial about their space. 

Enlarged Swim Bladder

Swallowing air to breathe and keep moving in the water is something most fish do. However, sometimes, the goldfish can end up taking in too much air. This fills up the air bladder more than its capacity and causes swim bladder problems. 

Over Feeding 

Improper feeding is one of the main causes of swim bladder issues in most goldfish. You don’t want to give too much food to your fish or give it something that is not recommended as fish food. 

When fish eat, they usually gulp down the soaked granules. These granules act like sponges and soak water from the fish’s mouth and digestive tract. When goldfish eat too much, the food settles in their stomachs and remains undigested. This causes swelling and presses against the swim bladders. 

The fish will find it hard to remain in an upright position. You’ll notice that the goldfish is swimming sideways with a bloated tummy. 

Water Temperature 

The aquarium water temperature and water quality can play an imperative role in the health of your pet fish. If your goldfish is exhibiting symptoms of swim bladder disorder, check the water temperature to ensure it is not too low. 

Cold water affects the digestive system. When the food, especially protein, is not properly digested, it produces excess gas in the gut. The gas will put pressure on the swim bladder and make the fish swim on its side. 

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Chemical Reactions 

We all know not to use any kind of chemicals in the fish tank. However, leftover traces of cleaning agents can affect the sensitive skin of the fish and lead to diseases like swim bladder disorder. 

Another way chemicals get into aquarium water is through the air. Using air fresheners, candles, insecticides, disinfectants, etc., in the room with the fish tank can cause the toxic components to dissolve in the water. 

When the fish come in contact with these chemicals, they show signs of swim bladder disorder and other health conditions. If most goldfish in the water tank exhibit the same symptoms, the reason is most likely a chemical reaction or bacterial infection that spreads through water.  

Treatment for Swim Bladder Disorder 

Once you have properly identified that your goldfish is suffering from swim bladder disorder, take it to a vet. However, it is not always possible to rush to a vet or even use veterinary medicine immediately to treat your pet. 

Try the following steps to take care of your goldfish with SBD.

Step 1: Move the Fish to Another Tank 

Treating the affected fish is easier when it is away from the others. Move it into a smaller or different tank with fresh water. This allows you to observe the waste (poop) it passes into the water. 

Step 2: Maintain Tank Water Quality 

Add two tablespoons each of aquarium salt and unscented pure Epsom salt (or non-iodized salt) for every gallon of water. 

Then, you have to set the correct water temperature (between 68°F and 80°F) and maintain it within the desired range throughout the treatment. The pH levels should be between 7.0 and 8.4, and the hardness of 10 to 20 dGH. 

Note: Don’t add salt to aquarium tank water unless the fish is ill. It can harm freshwater fish and lead to other issues. 

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Step 3: Stop Feeding for Three Days 

Don’t feed the goldfish for the next two or three days. During this period, you should check if it is passing waste. If the waste hangs from the anal pore or is a light color, it indicates constipation. The excreta may also have air bubbles in it. 

The three-day no-food period allows the goldfish to digest the existing food and clear its intestines by passing waste. Some goldfish regain their body balance and start swimming correctly after this period. 

Nevertheless, it is recommended to continue the treatment to ensure your goldfish is completely healed and the swim bladder disorder won’t occur soon after you put it back in its fish tank. 

Step 4: Feed Green Peas on the Fourth Day

On the fourth day, cook frozen peas to feed your goldfish. The shelled peas have to be soft and crushed so that they can be easily digested. Provide only small quantities of live food (worms) and green peas for a week. Peas act as laxatives and relieve constipation. 

The idea is to ensure a high-fiber diet to help its digestive system work correctly. Dry food will lead to constipation and cause the same problem again. 

Step 5: Use Antibiotics (if necessary)

Sometimes, the problem will not be solved despite diligently following the above steps. This indicates an issue with the immune system or a hidden bacterial infection. A broad-spectrum antibiotic usually helps, but don’t give your goldfish any medicine without consulting a vet. 

Step 6: Maintain Partial Water and Feed Less Food 

The fish’s swim bladder will take some time (a week) to recover. Reduce the water level in the tank to encourage your goldfish to swim more. Give it smaller amounts of food and increase the frequency. 

Use a water conditioner if the goldfish is lying upside with its belly exposed to the air. This will help prevent redness and pain in the exposed area.  

Don’t move the fish to the main aquarium until it exhibits normal behavior for a couple of days. 

Tips to Prevent Swim Bladder Disease in Goldfish 

Ensure Good Water Quality and Correct Temperature

Filling the tank with freshwater is not enough. Invest in a water quality testing kit to make sure that there are no viruses and bacteria in the water. High nitrate levels in water also result in swim bladder problems.  

The temperature should not be cold for most fish. The water has to be around 20°C and 23°C (68°F to 74°F) for goldfish, though 50°F to 80°F is considered a comfortable temperature level. 

Warmer water promotes faster growth but also reduces the lifespan of goldfish. Hot water causes stress, while cold water makes them lazy and reduces appetite. 

Avoid Excess Oxygen in Water 

Maintain water level and temperature. It is a good idea to regularly check the air filter system in the aquarium tank and adjust the levels to ensure the oxygen levels in the water are neither high nor low. 

Keep Aggressive Fish in Another Tank 

Does your water tank have other fish species along with the goldfish? If yes, make sure that they are not aggressive. It is safer to have a separate tank for aggressive fish to avoid fights and injuries. 

Say No Chemicals in the Room 

Eliminate chemicals from the room. Scented candles, air fresheners, etc., can seep into the aquarium water and harm the fish’s health in many ways. 

Pay More Attention to Goldfish’s Diet 

Soak food before feeding your goldfish. Wet food is easier to eat and digest than dry food. Also, remove the uneaten food to prevent rot in the water tank. Live food like bloodworms, daphnia, etc., are good in smaller quantities. 

Avoid overfeeding at all costs. It’s not likely for a fish to be underfed, so don’t worry about it. 

Don’t Delay Tank Cleaning 

Dirty tanks are the root cause of the main infections in fish. Remove debris as and when you see it. Rotten food and fish waste generate ammonia and bacteria. Periodically cleaning the tank will keep your goldfish healthy. It also increases the filter’s life. 

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Despite everything, the goldfish might end up with a permanently damaged swim bladder. In such cases, you can’t do much except make sure the fish feels comfortable and has just enough food to prevent bloating or constipation. You can continue to keep it in the partial water tank. 

In some cases, the goldfish automatically recover and get cured of swim bladder disease in a few months or even a year. So don’t lose hope. Follow the vet’s advice and provide extra care to the goldfish. 

Other Reasons for Goldfish to Swim Sideways 

Swim bladder disorder may not be the main reason for your goldfish to swim sideways or display erratic movements in the water tank. Check for all possibilities so that you can correctly diagnose the condition of your pet fish and help relieve its pain. 

Fin Injury 

A fin stuck in a plant or aquarium’s decorative items can hurt the goldfish and affect its movements. This causes the fish to swim sideways or slowly. You should ensure that the tank has no harmful objects to avoid such instances. 

Weakness or Old Age 

A goldfish recovering from injury will not have enough strength to swim properly. The movements will be irregular and uneven. Older goldfish may also show similar signs. They will swim close to the bottom of the tank and spend more time resting or sleeping. 

Ich and Poor Health

Observe your goldfish to see if it is scratching itself on the side. This is due to a parasite called Ich, which affects its scales and fins. This causes the urge to swim to the bottom and rub its affected side on the substrate. 

Fin rot, dropsy, and columnaris are other health conditions that affect goldfish. Your goldfish needs medical attention to get rid of the parasite, as it can spread to other fish in the tank. 

Ammonia Poisoning 

Excess ammonia in water can cause the fish to swim sideways and in circles. You will also notice the goldfish gasping for air or having lethargic movements. Immediately move the fish to a freshwater tank. Aerate the tank to reduce the ammonia levels. 

Ammonia is released into the water by rotten food and fish waste. It is also produced by dead and decomposing fish. 

Final Words 

A goldfish can live for ten to fifteen years when kept in healthy conditions. In many cases, swimming sideways is a temporary problem and can be healed with proper care. However, as the goldfish gets older, it also grows weaker and will prefer to lie sideways or use one-side flaps. 

Do your best to keep the aquarium neat and maintain the temperature levels. The next time your goldfish swims sideways, follow this checklist to identify the actual cause and help it feel better. The recovery rate usually depends on how well you care for your little goldfish. 


Can goldfish recover from swim bladder problems?

Yes, goldfish can recover from swim bladder disease in most instances. That said, swim bladders can be permanently damaged in some fish and they will continue to swim sideways. 

Why can’t my goldfish swim straight?

Goldfish don’t swim straight for various reasons, such as: 
Stress from being introduced into a new environment or some change it didn’t like
Swim bladder disorder 
Ammonia and nitrate poisoning 
External parasites that cause itch and irritation 
Whirling fish disease 
Just being playful and having fun 

Is swim bladder disorder contagious to other fish?

No, swim bladder disorder is not contagious. However, if the problem is caused by overfeeding, chemical reaction, cold water, or bacteria, other goldfish in the tank can also show the same symptoms. 

Why is my goldfish lying sideways?

The goldfish may be lying sideways due to the following reasons: 
Swim bladder disorder
Weakness due to old age 
Injury to a fin or other organ 
Simply resting/ sleeping after swimming for hours 

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