I don't have any Chromis....but I can't recall if they are "tough" or not. I think I've heard of people using damsels, though. I let my tank cycle for almost 2 months...tough with nothing in it, but the time passes relatively quickly. Plus, I used that time to setup my QT and actually had 2 clowns in quarantine during the cycle...so actually, I did have fish to look at!@tdileo I have heard of a lot of people doing it that way. Iv heard a lot of push back on it from here so I am try to stay clean. But now the clowns are removed and I keep seeing a lot to add Chromis, but like @Idoc said its possibly putting them in a tank to their Death. But it is hard to see the tank empty. Chromis are really hardy little fish though i'v heard.