Parasite eating organisms will not cure your tank of an ick infestation.
The cleaners will eat the parasite as it appears on fish, but the fish will become infected, re-infected, and re-infected again and again, before the cleaner can eat up the parasites if, to begin with, you are dealing with an all out ick infestation.
Ick has a 3-stage life cycle of approx. 23 days. In the tomite [free-swimming] stage, the parasite is infectious to fish. During this stage, the tomite’s goal is to find a host fish, or die trying. After they attach to the gills or body of a fish, they develop into the second stage, the parasitic trophont. This is the only stage where cleaner organisms can attach ick. During this stage they burrow into the fish, feeding on it’s tissues. Once well fed the trophonts stop feeding and develop cystic coverings. This becomes the inactive tomont stage. At this point, during this final stage, the cysts may stay trapped in the mucus of the fish, or fall off and sit on the bottom of the aquarium. Within 6 to 10 days hundreds of new tomites emerge looking for fish hosts and the cycle begins all over again, and again and again until something truly effective is done about it. Once ick is an active presence in the aquaria, having infested fish, it must be irradiated or it will always pose a threat to fish, and to any new fish introduced. The only time this parasite is truly vulnerable is during their free swimming stage. The standard treatment for Ick is copper sulfate or hyposalinity. Only in the free-swimming stage are these 2 treatments effective.
Now you might ask if the cleaner eats off all the parasite while they are on the fish, why then would ick ever have the opportunity to live on? Simple. Not all ick are in the same stage of their life cycle at the same time. Thus, while your cleaner is chomping on big fat parasites on one fish, the ick is developing on another. Or free-swimming. Or laying on the bottom of your substrate or LR. Perhaps with several cleaner organism in the tank, you might actually stay ahead of the game, but I wouldn’t really want to bet my expensive livestock on it. I also would not want my fish to ever see a 2nd round of ick if the cleaner just didn’t get ‘em all in the first round.
Not to say, however, that a cleaner is worthless. It certainly is not. I would certainly keep a cleaner in a fish tank, particularly a reef with fish. But to use these helpful critters to cure an all out infestation of ick...I’d say NOT.
