The only way to rid a tank of ICH is to remove all fish from the tank for a minimum of 30 days or treat the tank with copper. Copper would mean you would be left with a FO
tank as it will kill all inverts too.
Once the parasite is in the tank it will always be there and it will be in your fish. UNLESS you treat for it. Garlic does not kill the parasite. All it does is increase the appetite of the fish so they will eat. That will help them get stronger, maybe strong enough to survive. So now you are living with a ticking time bomb in your tank. Take a vacation or somehow let the water parameters get to be less than perfect and a full blown outbreak is waiting to occur.
When I had an outbreak in my 125 I bought a 30 gallon tank to treat all my fish in. I also bought a heater and powerfilter with a biowheel. I used HYPOSALINITY
to treat. Capturing the fish was not easy. I had to remove most of the LR
to do it. I put the LR
in some plastic bins while I was catching the fish. I thought I had lost a bi-color blenny as I could not find it anywhere. When I started putting the LR
back in the tank the blenny jumped out of a hole in a rock into the plastic bin. I scooped it up and put in the QT tank.
Yes, it's a lot of work. But, I have not had an outbreak since. I QT all new fish for 30 days before putting them in the DT to make sure I don't have to go through that again.
To summarize: There are two methods to rid a tank of ICH; 1. Remove and treat all fish outside of the tank for 30 days minimum (6-8 weeks recommended); 2. treat the tank with a copper based medication.
Garlic: What has been Studied Versus Whaat has been Claimed by Steven Pro