Okay here is all the info I can think of:
Tank is divided and filtered.
My fish hasn't eaten in I don't know how long.
He has one other tanks mate. I think i am going to move the sick fish to a 1g heated of course.
The temp is around 75 in the 10g
his tank mate is at the other end of 3 way divided tank
He has 2 fake plants, a small bridge and 1 heater at his end.
At the moment he has some bubbly liquid hanging from his stomach. It was not there last night. Please help!!