What do we have here, another secret shopper thread? Is this supposed to be real? Geez I hope not.
But, O.k., here we go...NO luis, they're not fleas. Your fish probably will not EVER have fleas in their lifetime or yours. It sounds like they have an infestation of ich, and shold not have been treated in the main display tank. Hopefully, this tank is bare, has no crushed coral or sand on the bottom, that there's no live rock, and no snails, hermit crabs or any other invertabrate life in the tank. If you treated the main tank with copper, then any calcacareous material (crushed coral, sand, coral skeletons, or live rock will absorb the copper into them, and will leach the copper back into the water for almost forever, rendering them worse than useless for a reef tank. I say worse than useless, because if you try to use them in a reef set-up, the copper that is trapped in the carbonate material will leach back out over time and will kill things like snails, hermit crabs, corals and anemones. You MIGHT be able to treat the water wqith carbon or cuprisorb and remove the copper from the water, and further remove it with water changes, but the copper in those things will always be there, and will always poison your system and kill the invertabrates in the tank...You MIGHT be able to use it in a strictly fish-only tank, but ever several years down the line, the potential for copper poisoning is too great to chance...
I really hope this is one of the RS hook threads. If not, I apologize for my attitude in responding, but I can't believe a regular member of the forums would do something like this without asking advice here first...
edit for spelling...