I have had one of the ultimate oddballs in my 55 gallon tank for about month now. He's a Butis Butis (Crazy Fish) he will float an swim upside down. Also trys to blend in with plants an deco holding still for a long time. Very unique an unusaul fish. I also have a Lepoard Ctenopoma not as odd but a cool smaller fish an good tank mates.
ive kind of started ballooning up my bichir collection lately. went from 1 ornate to 1 ornate 2 senegals and 2 delhezi. Also Keep a clown knife and sydontis eruptus which I think are still pretty oddball for most