Odd ball?

Among the few I acquired as Tiger Stripe Hissers, a few are black, which I consider maybe just black strings. But one little guy actually turned out to be a Madagascar Hisser after her last molt, guess she would join the other tank of nymphs of Madagascar Hissers before she's matured soon.

Maybe I should just separate the black ones  as well, since someone in allpet forum told me that they look like hybrid more than black string. What do you think?