Peppermints and commons???

different species, therefore they do not breed.

Just a bit of background on why i say that so solidly.

I have been breeding bristlenose for 12 years now, both commons and other species too such as the pep and the orange spot. I also am 4 weeks away from submitting my thesis in population genetics. Finally, I literally wrote the book on breeding bristlenose. I am in contact with lots of breeders across the country and am well familiar with their little projects and I get let in on their experiments and the results. For example, in aus there are some reds beginning to appear on the market. I've known about them for months now. Just not allowed to tell people. I know what people are up to in the realm of bristlenose, I also know a lot about population genetics and genetic mechanisms.

so its completely impossible for a common albino or marble etc.. to interbreed with a peppermint

as some ppl claim that they have but i havnt witnessed it.

yep

I too have heard the stories from people who pop up on a forum for 5 posts and say they have done it.

That's good to hear. What other ancistrus won't cross breed?

All the many color variations ( regular, albino, calico, blue eye, green dragon, super red, ect...) of the common BN will breed together because they are the same species.

Any other specie will not breed with the common BN. By definition, a species can only breed with themselves. Now I know some fish species can hybridize, like the swordtail and platy, but I have never heard if this happening with any Ancistrus species.