Males are generally considered big enough to breed once they reach 500 to 600 grams depending on who you talk to. I think the smallest anyone here has witnessed a male breed at was like 240 grams. The size of the male is not as important as the will of the male when it comes to breeding. I think the weight is more in reference to a common weight at which the will to breed comes out. Some still will not breed at that weight and others would be more than willing. It would just scare the heck out of me to stick a little 250 gram male in with a 2000+ gram girl.