Right now we have a 5 gallon tank set up with a peppered Cory catfish, tri shark, and another fish my sister picked out, (cant remember the name). With a few live plants. They are all very small at the moment. I know I need to upgrade to a bigger tank very soon. My question is what Gal tank do I need for a tri shark, and a peppered Cory catfish? I would also want a rainbow shark in with them, Is that a good Idea? Also my final thing is I know the Tri sharks are community fish so would I need to put in two more tri sharks in too keep him company?