I read through 7 pages of the thread and have not come across one hypothisis that BP is not a hybrid after all, but deformed red devel from in breeding. Deformed body popped up sparadically in all kind of fish inbreeding, and 99% of the time they were culled. But a few breeders valued the deformity, and line bred them into balloon molly, fancy gold fish and most recently BP. If you look at the body shape of fancy gold fish or balloon molly, they are essentially crooked spined fish like BP, not hybrid.
Hybridization in fish, unlike mammals, do not produce deformity or infertility. I am not aware of any hybrid African cichlids or CA cichlids that are deformed or infertile, and it is the very fertility of these hybrids that is the concern for polluting the pure gene pools.
My hypothesis is that BP is just a deformed Red Devel created accidentally by inbreeding Red Devel to accentuate the intense red, no difference from EBJD which is a deformed Dampsey created accidentally to accentuate the intense blue. Both BP ad EBJD have the pairing of the recessive genes that give them the intense color, but at the price of deformity and infertility.
