Hi This guppy became bloated 2 dats ago,today he bloated some more and he is spending alot of time hiding near the bottom. he's scales arent portruding. I havent seen white poop. Any ideas what is it? He is in a 70L tank with 8 other guppys, Theres an external filter and a heater, WC once a week 25% and water P are 0,0,7.