I had a slow burning ich outbreak in my display tank, I tried using various meds and treatments and just couldn't get a handle on it, if i pulled fish from the display tank to a 20g hospital they'd normally die from the stress of the move anyways so I changed up my game plan from the standard western medicine treat the disease and kill it however you must (chemotherapy lol) I decided to simply support the fish's immune systems themselves. So I upped my water changes to help pick off floaters (EDIT: parasites) and to keep everybody from having to fight off nasties in the water or deal with ammo/nites and then piled in hiding places and plants to give the fish lots of places to feel safe and calm, and then i started to feed them an extremely high quality diet, I mean ridiculous homemade stuff (there're articles all over this site with recipes) and added garlic to the recipies, I'd also add 1 drop of this garlic aquarium additive (refined garlic juice) per 10 G for visible parasites. After doing that I had fish passing parasites that i didn't even know they had. Since then I haven't lost a single fish, have no bloated bellies, no stringy stool and oh yeah...no ich. Keep in mind this is in a fresh water tank but I do think the concept transfers. Just get your fish healthy enough that their own immune system can beat the parasites.