I've been lately focusing more on plants than my fish in my 55g low tech. That's why I only have a kribensis and a black skirt tetra. Now it's time to stock up the tank. I've been a fan of schooling fish and looking forward to getting some. My top choices are cardinals, rummynoses, and harlequins. I'm just not sure if any of them are going to be compatible with the male kribensis. I might also be adding a few angelfish to the tank too. I also heard that big schools of 10 aren't attacked as much as a small group. Is it going to be compatible?