hey there, i seem to be having alot of trouble with my tank. everytime i do a water change my fish seem to die. i fill a bucket with tap water and condition it before i put in into the tank and everything but they just keep dying. i was told by the pet shop to do a water change every 2 days and by the way im going i will have none by the end of the week! my platy fry appear to be doing well, i have them in a breeder net hanging from the tank and i feed them the small fry liquid food also they get fish food every now and then. i feed the fish (guppies and platys) twice a day, not much each time, and i have a planted tank both live and plastic. i do have big mystery snails in the tank and am wondering if they could be the prob cause i have heard they are big waste producers. at the moment i have one guppy who looks like he is swimming for his life but just not moving anywhere and another one is sitting on the bottom of the tank and comes up every now and then for a swim but he has been doing this since i got him, i am more worried about the other one, can anyone fill me in??