Treating Ich in Marine Fish: The Fast Protocol

White spots appear on your clownfish overnight and by morning your tang is scratching against the rocks. That is marine ich (Cryptocaryon irritans), and it moves fast once it takes hold. The good news is that if you catch marine ich symptoms early and treat in a separate tank, you can usually knock it out in two to three weeks without touching your display or your corals.

What you need

• A bare quarantine tank, 40 to 80 litres depending on fish size, with a simple filter and heater
• Reef Revolution Quarantine (18 AUD) to condition and settle the fish before treatment
• Reef Revolution Parasite Remover (45 AUD) as your primary anti-parasitic dose
• A test kit and thermometer to keep parameters steady during treatment
• Optional: a UV steriliser running on the display sump to knock down free-swimming theronts and stop reinfection

Spotting it early

Look for small white grains, like salt sprinkled on the fish, especially around the fins and gills. Rapid breathing, scratching on rock or sand, and clamped fins usually show up a day or two before the spots are obvious. If you see this in one fish, assume the tank water carries the parasite too and move fast.

The protocol

1. Day 1: Move the fish. Net the affected fish into a bare quarantine tank filled with water from the display, topped up with fresh saltwater. Never treat ich directly in a reef tank, copper and most parasite treatments will kill corals and inverts outright.
2. Day 1: Stabilise first. Dose Reef Revolution Quarantine as directed to reduce stress and support the fish's immune response before hitting it with medication. A stressed, undosed fish fights infection poorly.
3. Day 2 onward: Begin Parasite Remover. Follow the dosing schedule on the bottle exactly, this is not a product to eyeball. Consistent dosing at the right intervals is what actually breaks the parasite's reproductive cycle.
4. Days 3 to 21: Maintain the cycle. Ich has a life cycle of roughly two to three weeks in warm water. Keep dosing on schedule and do not stop early just because spots disappear, that is the most common reason ich comes back.
5. Run UV if you have it. A UV steriliser on the main display, sized for your tank's flow rate, will kill free-swimming theront stages before they find a new host. It will not cure an already-infected fish, but it dramatically cuts reinfection risk for the rest of your stock.
6. Day 21+: Watch, then release. Once you've seen zero spots for at least a week past the treatment course, and the fish is eating and behaving normally, it is safe to move back to the display.

A note on copper

Copper treatment saltwater dosing is the traditional route for ich and it does work, but it is unforgiving. Copper needs daily test kit monitoring and precise dosing, too little does nothing and too much kills the fish. For most home tanks, an organic treatment like Reef Revolution Parasite Remover run through a full quarantine cycle is simpler and safer, with far less room for a dosing mistake.

Prevention going forward

Every new fish should spend three to four weeks in quarantine before it goes anywhere near your display, no exceptions. It is the single biggest thing that stops ich outbreaks before they start. Browse our marine aquarium setups or grab the hardware for a dedicated quarantine station from our hardware range.

Prices mentioned are accurate at the time of publishing and are subject to change. Please check the product page for the current price.