Pregnant or fat?

James Member Posts: 26
Hi guys,
this probably doesn't need to go into the emergency room but still. I have a pair of giant danios, when I got them they where small and usual sizes but then it got colder and now the girl (I think) is fat, she also has a small black dot down the rear end of her body. I have moved her and the other one into a private tank. Is this normal?