I dug my old 75 gallon aquarium out of the closet. Spent a couple weekends creating a new 3D backdrop out of foam block and quick-crete. I set it up so that water flows (although rather slowly) from left to right, with an overflow headbox (disguised as a boulder) on the left, and pick-up filters (not so disguised) on the right...all this to mimic an eddy in a small creek.
Why go through all this trouble?
Notice the color of his eyes!
My wife named him Norman Bates...well, because he's psycho. After giving him a few days to acclimate to the tank, I put 10 goldfish in there thinking he would eat on them as he got hungry. Nope...he ate 6 of them (which was all that he could cram in his gullet), and then proceded to kill the other 4 just for the heck of it. It also didn't take him long to swim up the flow coming out of the headbox and get stuck in it...so I had to build a screen over the discharge.
A couple interesting things I've witnessed already:
-He will actually wrap his body around a rock to hide.
-Goldfish are easy...but I've put wild baitfish in there that are smart enough to run and hide. He will actually hunt these baitfish, nosing around crevises in the rocks like he knows they're there. I assume he smells them or senses their vibrations.