Just a dip in malachite green does not kill the parasite. Most medications kill the free swimming form of the parasite. Ich goes through several stages in its life and most if not all medications kill it in its free swimming stage if I'm not mistaken. I know copper works this way. Check with the manufacturer of malachite green. What I do with my new fish is a FW and methylene blue dip for 3-5 min ( I've never lost a fish as a result of a FW dip), then QT for 2 weeks in a tank with low dose copper. I add the copper to the QT tank after the fish has settled in the QT tank for 3-4 days. I know alot of people will disagree with the method, but after battling ich in my 120g for a year its not worth the risk of introducing the parasite again and losing hundreds of dollars worth of fish. _________ 75g reef with Nova Extreme 8 bulb HO T-5 lighting, refuge, Remora skimmer, DSB, Seio powerheads, Acro's, LPS corals, assorted zoo's & mushrooms, Yellow Tang, Maroon Clown, Blue Cleaner Goby , Cleaner, Fire and Sexy Shrimp, Coco Worm, T.Crocea Clam, Derasa Clam
120g FOWLR, 260w Orbit power compact lights, Remora Pro skimmer, 30g DIY Sump/Refuge, DSB,Seio Power heads, Powder Blue Tang, Purple Tang, Flag Fin Angel, False Eye Puffer, Copperbanded Butterfly and a Moorish Idol  | 
Ich question 
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This would have been one dead fish. lol. 
