I think tho that one needs to balance having a species-only tank, with having fish that look good together., and won't hybridize. Being careful with your species selections, having correct male to female ratios, and paying attention to your fry are all important things when you decide to breed.
Another thing I've been told by a reliable source...hybrids don't necessarily know what they are, so they will tend to breed with anything. They may not recognize what female they are SUPPOSED to breed with, and will just breed.