before i started aquarium keeping i read books on quaruntining. i bought a cardinal that died in quaruntine after 3 days, and my emperor for my 150 got ick after two days in the quaruntine tank, but once i put him in the display tank he was as happy as a clam, i checked my nitrate levels and all, eveything was fine, i think it might have been due to the small space (its a 20 gallon) for the juvinile emperor but i dont know why the cardinal died. after that i just release my fish in the main tank (after dripping of course) and they all do very well. maybe i just dont know as much as i should about quaruntining fish