[mangoandmimi]

Yes it is correct that species should never be mixed or paired with different species. That isn’t to say it doesn’t happen - campbells & WW hybrids exist as a result of mixing of course to the point where the vast majority are not purebred. I’ve even seen russians and robos housed together in pet shops. Placing hamsters in with other rodent types sounds even worse. No species should ever be mixed. It’s also generally accepted that even dwarf hamsters are better kept alone than in same species pairs, as pets.