I've had a 20g ffish tank for years and this year for christmas/birthday I recieved a 55g fishtank with the heater and all the set up. Having 35 extra gallons now I figured I could have more fish or bigger fish now. I've read a good bit on the internet but wanted to ask you folks what is the right info and what is wrong. I want to go with Jack Dempsey cichlids and from what I read they are pretty aggresive. My main question is what other fish would go with this species? I was looking to get some sort of catfish also. From what I understand I should have a good bit of nice sized rocks with holes and caves for them to pass through so they can seperate. Will this species do good with other cichlids and if so what kind? Also how many fish of this type can fit into a 55g tank. Some things I've read say to get 1 or 2 males and 3 to 5 females and let them reproduce for your tank and not all of the fry will make it. Some I see say to buy all the fish I want at the same time and other say buy a species of fish to go with them that can keep the population from getting way out of control. I just want to know your thought on all this. Also whats better for a tank like this gravel or sand?