Ich (White Spot Disease)

Small white spots resembling salt or sugar grains, often paired with fish rubbing against rocks or decorations, are the classic sign of ich — one of the most common freshwater fish parasites. It spreads quickly to other fish in the tank, so treat the whole tank, not just the affected fish.

Why this happens

• Stress from sudden temperature changes, transport, or overcrowding weakens a fish's immune response, letting the parasite take hold.
• It's often introduced by new fish, plants, or decorations added without a quarantine period.
• Cooler water lets the parasite's life cycle run longer, making outbreaks more likely and harder to fully clear.

What to do next

1. Raise the tank temperature gradually to around 82-86°F (28-30°C) to speed up the parasite's life cycle so treatment can reach it.
2. Treat the whole tank with an ich medication or aquarium salt, not just the visibly affected fish — the parasite is present on fish that look clean too.
3. Continue treatment for the full course listed on the product, even after spots disappear, since part of the life cycle isn't visible.
4. Quarantine any new fish for 2-4 weeks before adding them to an established tank to prevent reintroducing it.

Frequently asked questions