Hi i have a 80L tank with 9 guppies and a small pleco{ temporary} abot four mounths ago one of the big guppys started to bloat and 2 days later one of the other smaller guppies passed. I treatedthe tank with Furanol antibiotic with no effect and the bloated one died a few days after. 10 days ago one of the big guppies bloated and to days after another small one passed. after that iv treated with Gyorodol{Praziquantel} and after 3 days the bloat was gone but today the fish died.. Im really asking for any help and suggestions.. Tank info: 700L/H external filter temp 26 water para:0,0,5 W every week 25% theres a small driftwood and natural quartz