I have a relatively new cycled tank, and I have just added 5 cories (after having 4 platies). I was thinking I would get all the same kind of cories, but on the last minute decided to get 3 julis and 2 emeralds. The woman at the store said they would school together, but they seem to be "segregating." Will they figure it out or do I need to get more of each? I have a 28g hex tank, so I was really thinking I needed to keep it to a small school. I am planning on adding 5 serpae tetras, and that will be complete.