I wouldn't do the knife fish. It just seems like a bad idea. The black ghost profile warns against doing it. I know thekoimaiden knows more on the subject so maybe ask her if you're curious about it.
A 180! Holy poop. The things you could do with that. With that tank I'd look into a giant gourami. :3 Giant redtail gourami stay slightly smaller at 20" than the others.. Or a 9" kissing gourami..
Hah, that's nothing.
I think the weirdest thing a fish does award goes to the frogmouth catfish.
This fish lowers the pH in the tank.. If you never did water changes it'd eventually burn itself in it's own acid. One of my favourites.
Hahahhaa, I love them. <3
Of course.. I have a thing for fish like that.
OH Sakura check this out- I'm going to heckle the LFS to get me one of these senegal bichir in (and getting a second species too). It's a long fin. :3 I think they look MAGIC.