Still trying to figure out these bocourtis. They range from 3 - 4 inches now. Two are noticeably bigger than the rest and eat more food, but they look different from each other. The largest one has very little color, a good bit of black along the lateral line, and is not very aggressive. The second largest one has very little black along the lateral line, has more small black specks on the sides, has a good bit more red and orange, and is much more aggressive. The other three look like small versions of the largest one that I first described. The second largest one (and the most colorful) has claimed a territory and defends it to no end. It also is a food hog along with the largest fish, and it actually pushes the larger fish around some. Can't get a feel for differences in body shape yet, but if one were to ask me I'd say the colorful, more boisterous one is more round than the others. Can behavior and color be used at all to get an idea of the sex of these fish?