How Do I Treat Ich (White Spot Disease) in a Reef Tank?
Quick Answer
Treating ich in a reef tank is challenging because copper-based medications kill corals and invertebrates. The most effective approach is removing infected fish to a quarantine tank for copper or hyposalinity treatment while keeping the display tank fish-free for 72+ days.
Marine ich (Cryptocaryon irritans) is one of the most common and frustrating diseases in reef keeping. The challenge is that effective treatments are toxic to corals and invertebrates, making treatment in a display tank nearly impossible.
Why Reef Tank Treatment is Difficult
- Copper kills corals - The most effective ich treatment is lethal to all invertebrates
- Hyposalinity damages corals - Low salinity stresses or kills most reef inhabitants
- No reef-safe cure exists - Products claiming to treat ich in a reef tank rarely work
The Proper Treatment Protocol
Step 1: Set Up a Quarantine Tank
You need a separate tank to treat fish. Even a basic 20-gallon tank with a heater, air stone, and PVC hiding spots works. Learn more in our quarantine tank setup guide.
Step 2: Remove All Fish
Transfer all fish from your display tank to the quarantine tank. Yes, all of them - even fish that appear healthy are likely carriers.
Step 3: Treat with Copper or Tank Transfer
- Copper treatment: Use Copper Power or Cupramine at therapeutic levels (2.0-2.5 ppm) for 30 days
- Tank Transfer Method (TTM): Move fish between sterile containers every 72 hours for 12 days
- Hyposalinity: Lower salinity to 1.009 for 6+ weeks (harder to maintain)
Step 4: Leave Display Tank Fallow
This is the hardest part. Your display tank must remain fish-free for at least 72 days (some recommend 76-90 days). The ich parasites need a fish host to complete their life cycle - without fish, they die off.
"Reef-Safe" Products - Do They Work?
Products like garlic extract, Kick-Ich, or other "reef-safe" treatments do not cure ich. At best, they may reduce symptoms temporarily while the fish's immune system fights the infection. Many fish appear to recover but remain carriers, leading to future outbreaks when stressed.
Prevention is Key
The best approach is preventing ich from entering your tank:
- Quarantine all new fish for 30+ days before adding to display
- Observe carefully for symptoms during quarantine
- Prophylactic treatment - many reefers treat all new fish with copper as standard practice
Learn more about proper quarantine in our fish quarantine FAQ.
Signs of Ich
- Small white spots on body and fins (like salt grains)
- Flashing/scratching against rocks
- Heavy breathing or lethargy
- Loss of appetite
Dealing with ich is frustrating, but following the proper protocol ensures complete eradication rather than a recurring problem. Track your treatment progress and quarantine timeline in the ReefBay app.
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