Common Medaka Diseases & Prevention Guide

Medaka are hardy fish, but they become susceptible to disease when overcrowded or when water quality deteriorates over time. Regular observation and proper management are fundamental to maintaining health, whether kept indoors or outdoors.

Common Diseases and Problems

White Spot Disease - **Symptoms**: Numerous white spots appear on the body; fish rubs against container walls - **Cause**: Ciliate parasitic infection. Common in early fall when temperatures drop - **Treatment**: Treat with methylene blue or salt bath (0.5%) for about one week. Raising temperature to around 28C improves effectiveness

Cotton Wool Disease - **Symptoms**: White cotton-like mold attaches to body and around the mouth - **Cause**: Aquatic fungi infecting wounds. Common during low temperatures and poor water quality - **Treatment**: Salt bath (0.5%) or methylene blue treatment

Overcrowding Stress and Oxygen Depletion - **Symptoms**: Gasping at the water surface (surface breathing), sluggish movement - **Cause**: Ammonia buildup and insufficient dissolved oxygen from overcrowding - **Treatment**: Immediately perform a large water change (50% or more) and reduce stocking density

Wasting Disease - **Symptoms**: Body becomes thin despite eating, and the spine appears curved - **Cause**: Complex factors including internal organ disease, parasites, and bacterial infection - **Treatment**: Isolate and provide high-nutrition live food (daphnia, brine shrimp)

Prevention Tips

Maintain a stocking density of 1-2 fish per liter. Keep up with regular partial water changes. For winter, maintain adequate water depth to prevent freezing to the bottom, and fasting during hibernation is standard practice.

Benefits of Buying on Buri-Choku

On Buri-Choku, you can purchase directly from breeders who specialize in selective breeding. You can verify bloodline, care environment, and feeding regimen in advance, welcoming healthy, acclimated individuals.