Diagnosing and Treating Sick Goldfish: Swim Bladder Issues and More

Recognizing the Symptoms

A goldfish hovering at the surface with clamped fins, not gasping but simply floating, often signals a swim bladder disorder. The dorsal fin held flat against the body is another clue. If the fish isn't eating and its tankmate appears healthy, the problem is likely internal rather than environmental.

Immediate Steps

1. Isolate the fish in a separate container to prevent potential spread of infection and to monitor closely.
2. Fast for 2–3 days. Constipation can press on the swim bladder; withholding food often allows the blockage to clear.
3. Check water quality—ammonia, nitrite, pH, and temperature. Warm water holds less oxygen, so ensure adequate aeration.

When to Suspect Other Causes

If the fish shows no signs of parasites, fungus, or bacterial lesions (white spots, red streaks, cottony growths), and water parameters are good, a swim bladder malfunction is the leading diagnosis. Unfortunately, chronic swim bladder issues in fancy goldfish often have a poor long-term prognosis, but the fasting method can provide temporary relief.

Tank Size Consideration

A 6.5-liter (≈1.7 gallon) tank is far too small for even one goldfish. Upgrade to at least 20 gallons for the first fish and 10 gallons for each additional one to maintain water quality and reduce stress.