Goldfish Swimming on its Side: Causes & Treatment

Goldfish are one of the most popular types of fish kept as pets due to their vibrant colors, easy care, and longevity. While goldfish are relatively hardy and can tolerate a range of water conditions, they are not immune to health problems.

One common issue that goldfish owners may encounter is their fish swimming on their side.

If you have noticed your goldfish swimming on its side, it may be a sign of an underlying health problem. In this blog post, we’ll explore the potential causes of this behavior and what steps you can take to help your fish recover.

Goldfish Swimming on its Side

Causes of Goldfish Swimming on its Side

Swim Bladder Disorder

The swim bladder in goldfish is a gas-filled organ located in the abdominal cavity. Its primary function is to help the fish control its buoyancy and maintain its position in the water column.

When the fish wants to rise or sink, it adjusts the amount of gas in the swim bladder by either gulping air or releasing it through the duct that connects to its esophagus.

This allows the goldfish to control its depth in the water and maintain a stable, upright position.

Swim bladder disease in goldfish occurs when the organ becomes inflamed or damaged, making it difficult for the fish to control its buoyancy and causing it to swim on its side or upside down.

If the swim bladder becomes damaged or infected, it can cause the fish to swim abnormally, including swimming on their side.

Swim bladder disorder can be caused by various factors, including overfeeding, bacterial or parasitic infections, and physical injury.


Goldfish are notorious for their voracious appetites, and overfeeding can lead to constipation. Constipated fish may have difficulty expelling waste, leading to bloating and swimming difficulties.

Spinal Injuries

Spinal injuries can cause a range of issues, including swimming on their side. Injuries may be caused by physical trauma or underlying health conditions like scoliosis or other deformities.

Spinal injuries in fish can also occur as a result of trauma, such as being dropped, netted, or attacked by other fish.

These injuries can cause damage to the fish’s spinal cord, nerves, or muscles, which can result in a range of symptoms, including disturbed swimming behavior.

When a fish experiences a spinal injury, it may have difficulty swimming upright, or may swim on its side or upside down.

It may also struggle to maintain balance, or experience spasms or convulsions. In severe cases, the fish may become paralyzed and unable to move.

Treatment for spinal injuries in fish depends on the severity of the injury and the underlying cause.

Mild injuries may heal on their own with time and proper care, while more severe injuries may require supportive care, such as antibiotics or anti-inflammatory medication, to help reduce inflammation and prevent infection.

In some cases, fish with spinal injuries may never fully recover, and may experience permanent swimming difficulties.

These fish may require special accommodations in the aquarium, such as a shallow water level or specially designed resting areas, to help them swim and rest comfortably.

Internal Parasites

Parasites like worms or flukes can also cause swimming difficulties in goldfish.

These parasites can live in the fish’s digestive tract, organs, or tissues, and can cause a variety of symptoms such as loss of appetite, weight loss, lethargy, abnormal swimming behaviors and even death.

Some of the most common types of internal parasites in goldfish include roundworms, tapeworms, flukes, and protozoa. These parasites can be introduced into the aquarium through contaminated water, food, or live fish.

To treat internal parasites in goldfish, it is important to first identify the specific type of parasite present. This can be done through a microscopic examination of a fecal sample, or through an examination of the fish’s gills, scales, or internal organs.

Treatment options for internal parasites in goldfish typically involve the use of medication, which may be administered orally or added to the water.

Preventive Measures

Check water quality: The first step to helping your goldfish recover is to ensure that their water quality is optimal.

Test the water for levels of ammonia, nitrite, nitrate, and pH, and take steps to correct any imbalances. Consider performing a water change to dilute any pollutants in the water.

Adjust feeding habits: If your goldfish is constipated, adjust their feeding habits to reduce the risk of overfeeding. Feed smaller, more frequent meals and consider offering high-fiber foods like peas to help alleviate constipation.

Quarantine: If you suspect that your goldfish may have an infection or parasite, consider quarantining them to prevent the spread of disease to other fish. You can treat the fish with medications or seek the advice of a veterinarian.

Observe behavior: Keep a close eye on your goldfish’s behavior and look for any signs of improvement or worsening. If you notice any changes, adjust your treatment plan accordingly.

Physical Treatment

a. Adjusting the diet: Feed the goldfish a diet that is high in fiber and low in protein. Overfeeding can cause constipation and bloating, which can lead to swim bladder problems.

Try feeding them peas, boiled spinach or other high fiber vegetables, and avoid feeding them too much commercial fish food.

b. Water temperature: Keeping the water temperature stable, within the range of 68 to 72 degrees Fahrenheit, can help alleviate swim bladder problems.

c. Water quality: Ensure the water is clean and adequately oxygenated. Regularly change the water and use a filter to keep it clean.

Chemical treatments

a. Epsom Salt: Epsom salt can help to alleviate constipation and bloating in fish. Add one tablespoon of Epsom salt per gallon of water to the tank for a few days.

b. Antibiotics: Sometimes, bacterial infections can cause swim bladder disease. Your veterinarian may recommend an antibiotic treatment for the fish.

c. Medications: Some medications, such as Metronidazole or Antibacterial/Fungal treatments, can help alleviate swim bladder disease caused by bacterial infections.


Can swim bladder disorder be cured?

In many cases, swim bladder disorder can be treated successfully.

However, the success of treatment will depend on the underlying cause of the disorder and the severity of the fish’s condition.

How can I tell if my goldfish has swim bladder disease?

Signs of swim bladder disease in goldfish include swimming on its side or upside down, difficulty swimming or staying upright, loss of appetite, and lethargy.

What should I do if my goldfish is not responding to treatment?

If your goldfish is not responding to treatment for swim bladder disease, you should seek the advice of a veterinarian who specializes in fish health, as there may be underlying health issues that require further diagnosis and treatment.