Guppies Dieing and i dont know why

GaD

New Fish
Dec 16, 2003
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#1
For some reason a guppy will hide, hang out right behind my heater or ontop of the suction cup and within a day or so hell be dead, I tested my water and all tested good, amonia/nitrates=0 & ph was good. Water is crystal clear. The fish after its dead shows no sign of ich, sores or physical damage. After i notice them in the "death spot" i notice they start nose upping here & there.

Any help would be greatly appreciative,.

I have a 5gallon biowheel tank w/ heater & a real plant if that helps.