I have started my tank cycle... I put fish in (3 damsels) my 55gal about 4 weeks ago. About 1.5 weeks ago the last of them died. Does there need to be constant ammonia producing liveforms, or decay for the cycle to finish out or should it be about time for me to get the test kit (nitrate, nitrite) and be on my way to some longlived fish? I have no live rock and a 5-6" sand bed. The sand bed had no live sand in it yet it's more for looks now than anything. Thanks