I have a tank I inherited from my mother when her last fish died. I think it is either a twenty or twenty five gallon bow front tank. I have been trying with it for three years. After one round of a complete tank death, save one black Molly that died less than six months ago finally... And moving the tank to my new home, and surviving multiple rounds of ick over nine months (what finally got the Molly) I have whittled my fish down to two types. So far it seems to work. I have eight fish total in the tank. 1 year old blue gourami Newish golden gourami 2 powder blue gourami newish 2 dwarf gourami, one newish and one about six months in the tank. And two emerald Cory cat fish. Newish Newish meaning like two months. It's not real decorated. I have a volcano and a small sponge bob figurine bubblers (thank you ten year old for the sponge bob.) I have three medium sized plants and two small ones. I run an Aqueon quiet flow 10 power filter, & the heater that came with it I clean it regularly. I use water conditioner (top fin). I change the filter every month or month and a half, like I'm supposed to. Nothing works! The water is always cloudy. Sometimes it's a yellow cloudiness. Sometimes it's just cloudy. It's annoying. Any help?