Are your Eastern's in the "eft" stage? Because I have seen many Easterns in the wild that have what could be described as a black pigment when looked at closely. It doesn't make them completely black; they are still orange, but when you look up close you can see dark pigment on some of them. Also, when the efts become adults and return to the water, they become much darker, like a brownish green. So that could also mean that they are nearing maturity. Ofcourse, it could be something else altogether! Just wanted to share my observations.
