my female guppies, mollies, and comets like to swim realy fast up and down my aquarium's corner. is this regular behavior? my mollies and comets like to bite the tails of my guppies and tetras. i think thats a bad thing. my male guppy is like swimming at the top of the aquarium and hardly going deeper... is that bad? i had a female guppy that died a day after being put into the aquarium. it had hard time staying stable and had gunk in her mouth. she didnt open her mouth and stuff. i think thats the disease that i forget its name. one of my comet has lost like 4 of its fin; the dorsal the anal fins and the ones in front of the anal fins. will they grow back? can anyone tell me if any of this behavior and conditions are normal? thanks.