I've been raising and researching sb Texas for the better part of two years now, again I've yet to see an sb texas that was NOT a hybrid. If some one can provide proof positive that carpintis carries a naturally occuring sb gene PLEASE, I'm begging you, step forward and produce it!
A black marking in the dorsal does NOT indicate fertility in my experience, in fact I've never heard of such a thing. In my experience it indicates an immature fish of either sex or a mature female. You can expect males to reach approximately 6" and females approximately 5"
Oh and p.s.? my sb Texas were bred using an imported HYBRID sb texas crossed to a pure carpintis from Rapps...no inbreeding, no naturally occurring sb carpintis gene.