i keep yellows and cpo's together in a couple of tanks. I have yet to see one get caught and both populations are pretty large and growing (15-20 cpos of various gens, and over a hundred yellows per tank). the tanks are 30B though and heavily planted and scaped (rocks or pots and such). i also feed well and that is the key, mainly done to keep the damn cpos from eating each other when they molt. i seem to lose more cpo's from breeding, the males get ultra agressive and end up tearing off most of the females legs (smaller females). i sepparate them when i can, but still lose a female from time to time. i try to remove excess or bad tempered males when i see them and that helps. but back on topic, i have yet to see an issue with mixing neos and cpo's (i also keep my snowball breeding colony with white p clarkii with no problems). crays tend to be alot harder on their own kind than shrimps IME anyway.