If you’ve noticed your gourami swimming on its side, you’re likely worried. This unusual behavior signals that something is wrong with your fish. While it can be alarming to see, the good news is that many cases are treatable when caught early.

When a healthy gourami swims, it maintains an upright position with smooth, controlled movements. A gourami swimming on its side has lost its ability to control its buoyancy and balance. The fish may tilt at odd angles, struggle to stay level, or even float belly-up while still alive.

This behavior is not normal. It indicates an underlying health problem that needs your attention. The sooner you identify the cause, the better your chances of helping your fish recover. 

This article explains why gouramis swim sideways, what you can do to help, and how to prevent it from happening again.

Common Causes of Sideways Swimming in Gouramis

The main reasons for gouramis swimming sideways include:

Swim Bladder Disorder

The most common reason gouramis swim on their side is swim bladder disorder. The swim bladder is an internal organ that helps fish control their depth and maintain balance in the water. When this organ malfunctions, the fish loses buoyancy control.

Several factors can damage or disrupt the swim bladder. Overfeeding is a frequent culprit. When gouramis eat too much, their digestive system swells and puts pressure on the swim bladder. Constipation can also compress this delicate organ, making it impossible for the fish to swim normally.

Sometimes the swim bladder becomes infected or inflamed due to bacterial or parasitic infections. Physical injury from aggressive tank mates or collisions with decorations can also damage it.

Poor Water Quality

Gouramis are sensitive to water conditions. When ammonia, nitrite, or nitrate levels rise too high, these toxins stress the fish and weaken its immune system. Prolonged exposure to poor water quality can lead to organ damage, including problems with the swim bladder.

Low oxygen levels also affect gouramis, even though they can breathe air from the surface using their labyrinth organ. When water quality deteriorates, fish become sluggish and more susceptible to illness.

Bacterial or Parasitic Infections

Internal infections can cause inflammation that affects the swim bladder and other organs. Bacterial infections may develop from contaminated food, dirty water, or stress that weakens the fish’s defenses.

Parasites can also invade the digestive system or swim bladder, causing similar symptoms. You might notice other signs like weight loss, loss of appetite, or unusual coloring alongside the sideways swimming.

Temperature Shock

Sudden changes in water temperature can shock a gourami’s system. These fish prefer stable temperatures between 75-82°F (24-28°C). A rapid drop or spike can stress the fish and temporarily affect its swimming ability.

Injury or Birth Defects

Physical trauma from fights or accidents can damage a gourami’s swim bladder or spine. In some cases, fish are born with deformed swim bladders that eventually cause balance problems as they grow.

How to Diagnose the Problem

Start by observing your gourami closely. Note any other symptoms beyond the sideways swimming:

• Is the belly swollen or bloated?
• Has the fish stopped eating?
• Are there visible wounds or unusual spots on the body?
• Is the fish breathing rapidly or gasping at the surface?
• Are other fish in the tank affected?

Next, test your water immediately. Use a reliable test kit to check ammonia, nitrite, nitrate, pH, and temperature. Write down the results so you can track any changes.

Check your feeding routine. Have you been feeding more than usual? What type of food are you using?

Look at the overall tank environment. Is there enough space? Are tank mates peaceful or aggressive? Is the filter working properly?

Treatment Options for Sideways Swimming

This is how you can save your fish from this problem:

Step 1: Improve Water Quality

Begin with a 25-30% water change using dechlorinated water that matches the tank temperature. This helps dilute any toxins present.

Test the water again after the change. If ammonia or nitrite levels are above zero, or if nitrates exceed 20-40 ppm, continue doing daily water changes until levels stabilize.

Make sure your filter is clean and functioning properly. A clogged filter can’t remove waste effectively.

Step 2: Fast Your Gourami

If overfeeding or constipation seems likely, stop feeding your gourami for 2-3 days. This gives the digestive system time to clear and reduces pressure on the swim bladder.

After the fasting period, offer a small piece of cooked, shelled pea. Peas act as a mild laxative for fish and can help relieve constipation. Mash it slightly and offer just a tiny portion.

Step 3: Adjust Temperature

Ensure the water temperature is stable and within the ideal range (75-82°F). Use a reliable heater with a thermometer to monitor it.

If the fish experienced temperature shock, gradually bring the temperature to the optimal level. Don’t make sudden adjustments.

Step 4: Quarantine If Needed

If you suspect infection or want to treat the gourami without affecting other fish, move it to a hospital tank. A 5-10 gallon quarantine tank with gentle filtration and hiding spots works well.

Quarantine also reduces stress by removing aggressive tank mates from the equation.

Step 5: Medication

For bacterial infections, consider using a broad-spectrum antibiotic designed for fish. Follow the dosage instructions carefully.

If you suspect parasites, an anti-parasitic medication may help. Again, follow directions precisely and complete the full treatment course.

Only medicate if you have clear signs of infection beyond just the swimming issue. Unnecessary medication can stress fish further.

Step 6: Add Aquarium Salt (Use Carefully)

Some fishkeepers use aquarium salt to help with swim bladder problems. Salt can reduce stress and support healing. However, gouramis are freshwater fish, so use salt sparingly and only as a temporary measure.

Dissolve 1 tablespoon of aquarium salt per 5 gallons of water in the hospital tank. Monitor the fish closely. Don’t use salt if you’re already medicating.

Recovery Time and What to Expect

Recovery depends on the cause and severity. If constipation is the issue, you may see improvement within a few days of fasting and dietary adjustments.

Swim bladder damage from infection or injury takes longer. Some fish recover fully in 1-2 weeks with proper care. Others may show gradual improvement over several weeks.

Unfortunately, severe swim bladder damage or birth defects may be permanent. In these cases, the fish might never swim normally again. You’ll need to decide whether the fish can still have a decent quality of life or if humane euthanasia is the kindest option.

Prevention: Keeping Your Gourami Healthy

You can prevent this problem from recurring as follows:

Feed Properly

Offer small amounts of food 1-2 times daily. Only give what your gourami can eat in 2-3 minutes. Overfeeding is one of the easiest mistakes to make and one of the most harmful.

Use high-quality food designed for gouramis. Vary the diet with pellets, flakes, frozen foods, and occasional vegetables. Soaking dry food before feeding can prevent it from expanding in the fish’s stomach.

Maintain Excellent Water Quality

Test your water weekly. Keep ammonia and nitrite at 0 ppm and nitrates below 20 ppm through regular water changes.

Additionally, change 20-30% of the water every week. Vacuum the substrate to remove waste and uneaten food.

Remember to do proper tank cycling before introducing your fish.

Provide Proper Tank Conditions

Gouramis need adequate space. A single gourami does well in a 20-gallon tank, though larger is always better. If keeping multiple gouramis or a community tank, increase the size accordingly. Ensure the following:

• Keep the temperature stable with a quality heater. 
• Avoid placing the tank in areas with drafts or direct sunlight that cause temperature swings.
• Ensure good filtration without creating strong currents. Gouramis prefer calm water.

Choose Compatible Tank Mates

Avoid aggressive fish that might nip at or stress your gourami. Male gouramis can be territorial with each other, so choose tank mates carefully.

Peaceful community fish like tetras, corydoras, and rasboras generally work well.

Reduce Stress

• Provide hiding spots with plants and decorations. Gouramis appreciate cover and resting areas.
• Maintain a consistent lighting schedule. 
• Avoid sudden changes to the tank setup that might startle fish.
• Keep the environment quiet and place the tank in a low-traffic area.

When to Seek Help

If your gourami doesn’t improve after a week of treatment, or if symptoms worsen, consult an aquatic veterinarian or experienced fish specialist. While not common, some areas have vets who treat fish.

Online forums with experienced fishkeepers can also offer advice, though be cautious about conflicting information.

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Final Thoughts

Seeing your gourami swim on its side is concerning, but many fish recover with prompt, appropriate care. Start by improving water quality and adjusting feeding habits. These two steps alone solve many cases.

Pay attention to your fish daily. Early detection of problems gives you the best chance of successful treatment. With proper care and a healthy environment, your gourami can return to swimming normally and live a full, happy life.

Remember that fishkeeping is a learning process. Even experienced aquarists face challenges. What matters most is that you’re willing to observe, learn, and take action when your fish needs help.