how many polys are you interested? and would you like upper or lower jaw. I would suggest upper because they don't get as big (except ornate and weeksi) and you can have more. I would defiantly you have to have a delhezi, ornate, weeksi, moke, and i would say palmas polli, and palmas buettikoferi. For tank mates I would stay with medium to top tank level fish. for medium i would say red tail shark. People can disagree with me but i had 1 and he was amazing i would feed my polys meaty foods and he would eat the remains he also ate the algae of the tank. He was like a super pleco. But i would get a couple of red tails. Possibly some tiger barbs? not real sure on them. But as far as top cover i'm not really sure.