the yellow fish ... looks a bit like a platy and a bit like a molly. I understand that they can interbreed so you could have a cross breed. I have one that was sold to me as a red wagtail platy and as a young fish she was every inch a platy but as she's aged - and grown massively her face is the wrong shape for a platy. She's also too big to be a platy so I'm sure she's a platy/molly cross.