I don't think the ick treatment would hurt them. It's only malachite green and something else. Mostly called Ick-Away or Cure-Ick, something to that effect. WalMart or Petsmart will most likely have it. ust remember you can't use your filter at that time while treating, because the carbon filters it out. Like you said, the most sensible thing to do is just treat the whole tank. Seems to work better IMHO. Good luck to you, hope everything gets cleared up