Ammonia was tested at 0.50 today. What I called "really high" after the break was water was a reading of 1. Nirtite is 0.5, and nitrate is 5. The tanks is kept at a temperatue of 80 F, and the temperature does not fluctuate, as far as I know. I've been in the school on weekends, and tracked the temp before I added the fish. The tank is set up in the corner of the room, under a window. It has 2 airstones, 2 heaters, and an over-the-back filter. I know that except for the week when no one was able to get into the school, they are not under fed. I feed them 1 cube of spirulina, brine shrip, and mysis frozen aquarium food every other day, as per the recomendation of Sean at F&F. The other fish have grown visibly since I got them. I think that the deaths could be due to stress. The 1st fish died less than a week after he was put into the tank. The 3rd fish (a runt) died a few days after the snow break, which I know was stressful for the fish. I don't know if the fish in the middle died of natural causes, or if it was killed by the other fish over the break, because the body was eaten by the other fish. I hope that this info helps!