They are not a very active fish so tank size is not criticle as long as they can turn around, I think anything from a 29g on up would be okay. Don't know the current prices. A friend had one some years ago that wouldn't take food that was not moving, he solved that by using chunks of bait fish dropped one at a time into the powerhead flow so that they washed over the head of the three-spine. It would also take prawns from a pair of chopsticks.
