Jeez, I hate to post this, and I apologize to OP because absolutely no offense is intended. But IMO if your fish survived ich while you fed them garlic, this was a coincidence A post hoc, ergo propter hoc kind of thing. Please correct me if I'm wrong, and who says I'm not) but I have not seen ANY scientific studies that have found garlic can prevent or treat ich.
Mike
Hi Mike.
No offense taken.
this is my story....
I have two reef set up. One is 65G and the other is 165G. Both have very complex aquascaping that does not allowed to remove fish and quarantine it.
I know only two methods of treating ICK in the tank and those are
1: quarantine the fish and treat the tank and fish with copper.
2: Hyposalenity.
Both choices will wipe out everything in your tank except for fish.
Most of the aquariums do have ICK parasite larva but fish shows no visible signs of it due to good immune system response.
When your fish is stressed for whatever reason, the immune response goes down as well as protective coating on the fish. ICK is an opportunistic parasite and it will affect the stressed fish. that is why you can have sick and healthy fish in the same ecosystem. Same works for people. in a winter time you can work with sick people around you and don't get sick. I am a doctor and I know a bit about sick people, just a bit. lol.
The reason why I do garlic treatment for fish, as well as people, is to improve their immune system and help their body to fight the parasite. I also supplement fish food with vitamins and essential fatty acids. I do the same with people.
In fish, it improves the eating response, and also saturates their blood with garlic oil.
As we know, ICK parasite is feeding on fish blood. They are also live in a short range of favorable conditions for them. when those conditions are not met they look for a different host which is weaken buy stress or disease.
So, to make the long story short, this is my reasons why I do garlic treatment.
I can't take the fish out, so I do what i can to deal with this condition in the tank.
I also ran UV sterilizer with 35W and capability to do at least level 1 sterilization. that helps to keep the level of free swimming parasite down. It does not kills all ICK parasites, but keeps their number low. The sterilizers that can't do Level 1 sterilization will do nothing for your ICK in the tank, so no point of spending money on those.
Also, my 65G system has no UV sterilizer, and I was able to achieve the same results in regards to ICK.
I write this only to share my personal experience with fighting ICK repeatedly on several occasions. Every time i did that, I was aware that there is a high chance of me loosing my life stock, and it was my conscious choice still to go forward.
All those time it was a success.
Is it going to be the same result for you? I don't know.
All I know is ICK can wipe your system in a matter of days, and a lot of times i don't have ability to catch the fish and quarantine it before its too late. So garlic is what I do.
I hope that was helpful in any way.