I've read it's impossible to breed this in captivity unless I had kg's of hormones to add to my tank, but I have noticed out of my 10: 6 of them are looking very round in comparison to the other 4, like almost double and fat even upto the tail.
Is this an indication that they're females?
Another thing, I've seen them often side by side (2 at a time) just shimmying - leaning against each other and almost vibrating. Is this mating behaviour??