yes, that is why you leave it fallow with just the inverts and live rock for the 6-8 week ich life-cycle period.......then treat all the fish to a nice hypo salinity vacation in the quarantine....with some interesting pvc pipes to play hide and seek in. Remember to throw a sponge or something from your main tank into the qt to cycle it in a hurry......and keep up on water changes as you won't have live rock to house beneficial bacteria in...