I might be selling my 55 gallon set up and buying a 75 gallon set up from a friend, I have not set up the 55 yet because I have such a hard time deciding what fish to get but I think I want an oscar and a few large tankmates. I am still open to suggestions on what fish to keep in the new 75 so any suggestions would be nice, but if I get an oscar what are some good large tankmates that are fairly active?