Ich (White Spot Disease)
The most common aquarium disease. Caused by the parasite Ichthyophthirius multifiliis. Looks like salt grains on the fish's body and fins.
Check these symptoms in your tankSymptoms of Ich (White Spot Disease)
- White spots on body/fins
- Scratching against objects (flashing)
- Rapid gill movement / labored breathing
- Fins clamped against body
- Lethargic / hiding more than usual
How to treat Ich (White Spot Disease)
- Raise temperature gradually to 82–86°F to speed up parasite lifecycle
- Add aquarium salt (1 tsp/gallon) if species tolerates it
- Use ich medication: Ich-X, Kordon Rid-Ich, or API Super Ick Cure
- Continue treatment 1 week after all spots disappear
- Vacuum substrate thoroughly to remove cysts
How to prevent it
- Quarantine new fish for 4 weeks before adding to main tank
- Maintain stable water temperature, fluctuations trigger outbreaks
- Reduce stress: proper hiding spots, appropriate tank mates
Conditions with similar symptoms
Saltwater equivalent of freshwater ich. Caused by Cryptocaryon irritans. More difficult to treat than freshwater ich.
Caused by a dinoflagellate parasite. Appears as a fine gold or rust dust on the fish. Highly contagious and fast-moving, often fatal if not treated immediately.
Includes skin and gill flukes, anchor worms, and fish lice (Argulus). Fish may scratch against objects (flashing) and produce excess mucus. Often introduced with new fish or live food.
Not sure? Use the symptom checker
Many fish diseases look alike. Pick the symptoms you see in the free fish disease checker to compare likely causes, or scan a test strip to rule out a water problem first.