New Fish In The Tank

For some crazy ass reason one of the first things I set up in my new home was a 55 gallon aquarium. I have another 35 gallon tank in the corner, It's one of the 5 sided tanks made to fit into the corner of a room. Nobody in the 35 yet I'm trying to find some "old school" green sail fin mollies for it but a couple weeks ago I finally got some babies for the 55. A red tiger oscar, red fin (or rainbow) shark and a plecostemus. Feel free to spell check on the pleco! Anyway, the oscar is already visibly larger than when I brung him home. I had several in assorted talks when I lived in Colorado, developed a relationship w/ the pet store owner and would get nickle sized babies, grow them to hand sized and trade them for more babies, tanks, etc.