Goldfish Swim Bladder Disease: Causes and Fixes

Swim bladder problems are one of the most common health issues in fancy goldfish. A fish may float to the top, sink to the bottom, or swim sideways or upside down. It looks scary, but many cases can be fixed if you act early. Here is what causes it and what to do.

What Is the Swim Bladder?

The swim bladder is an organ that helps a fish stay balanced in the water. When it does not work well, the fish cannot control its position.

Why Fancy Goldfish Get Swim Bladder Problems

Fancy goldfish like Ranchu, Oranda, and Lionchu have short, round bodies. Their organs are squeezed together, so the swim bladder is more easily affected.

Common Signs

• Floating at the surface or stuck on the bottom
• Swimming sideways, tilted, or upside down
• Struggling to dive or stay level
• Swollen belly
• Not eating or being less active

Common Causes

• Overfeeding: A full stomach presses on the swim bladder.
• Dry or floating food: Fish swallow air and the food swells.
• Constipation: Too little fiber in the diet.
• Cold water: Slows digestion.
• Poor water quality: Stresses the fish and can lead to infection.
• Infection or injury: Less common, but possible.

How to Treat Swim Bladder Problems

1. Test your water. Ammonia and nitrite should be 0. Do a water change if not.
2. Fast the fish for 24 to 48 hours. This gives the gut time to clear.
3. Feed a blanched, shelled pea. Peas have fiber and help with constipation. Feed a small piece.
4. Keep the water steady. A temperature around 74 to 78°F can help digestion. Avoid big swings.
5. Lower the water level if the fish struggles to reach the surface. This makes it easier for a floating fish to move around.
6. Switch to soaked sinking food when you start feeding again.

If there is no improvement after a few days, or you see red streaks, sores, or a pinecone look in the scales, the cause may be an infection. Contact an experienced aquarist or a fish vet for help.

How to Prevent Swim Bladder Problems

• Use sinking pellets and soak them before feeding. See what to feed fancy goldfish.
• Feed small amounts one or two times a day.
• Add peas to the diet now and then.
• Keep water clean with weekly changes. See our water change guide.
• Keep temperature stable.

Frequently Asked Questions

Can a goldfish recover from swim bladder disease?

Many do, especially when the cause is overfeeding or constipation.

Is swim bladder contagious?

Not by itself. If an infection is the cause, other fish could be affected, so watch them.

Should I use medication?

Only if you believe there is an infection. Fix the diet and water first.

Why does my Ranchu float?

Ranchu are very prone to this because of their body shape. Our Ranchu care guide covers how to feed them to prevent it.

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