I've found a few places that say Rainbow cichlids can co-exist peacefully in community tanks (that have platies, tetras, etc.), is this true? When I upgrade to a larger tank, I was considering getting a pair (they need to be kept in pairs to feel secure, right?). I'm adding American Flagfish and Cardinal Tetra as well, plus the platies and black neon tetra in my current tank. I was thinking of upgrading to a 30 gallon. Would this sort of stocking be doable for the size/type of fish?