Hello. My husband and I set up a 30 GAL fish tank a few weeks ago. We used spring water and let the tank sit for 3 days while the heater warmed the water to 78. After 3 days we went to Walmart - which I know isnt a very good place to buy fish but the only place around here - and bought 4 glow fish, 2 angel fish, an alige eater and one black moors fish. All the fish have died in the past week except the 4 glow fish and the alige eater. The water is crystal clear and the temp is still at 78. Wonder what killed those fish? I dont want to buy anymore because I feel like a murderer! Any thoughts?? Thanks for your time. *SUNSMILE*