I'm a new Nano owner and I recently stocked my tank with a few fish: 2 clowns, a purple Firefish, and a cleaner shrimp (Already had BTA, corals, and CUC). I think my firefish died though. I have not seen it in the past 48 hours (usually is outgoing for a firefish and swims at the front of the tank with my clowns). I haven't given up hope that he may be hiding inside my porous rock, but he didn't even come out for food unlike before. Assuming he has moved on, should I be concerned about a spike in my nitrates? Are there any other water quality concerns I should monitor? I don't have a refugium or UV sterilizer set up yet. I hope he surprises me and shows up, but I don't wanna be caught sitting on my hands should something happen. Thanks in advance for the advice.