Is it better to keep demasoni in large groups? What is the minimun size aquarium you would keep 15 of them in? What are the best ways to keep their aggression down? If there is a cave for each fish, would I be able to keep up to 5 males in a single aquarium with the rest females or will they still kill each other? I'm trying to build the perfect atmosphere for around 15 of them. Is it possible?