I never kept on in a fish tank nor did I ever bring them home when I catch them from fishing...They do get huge. I caught a 24"+ once...(That was when I went Catfish fishing)
from what i hear from every body there good eating like all drums so last year after catching like 40 which most of them swollowed the hook and most likly died, i decided to keep them next year and give them to my grandpa if i dont like the taste
They get fairly large, so keeping them in anything less than a pond probably won't work. They do tend to swallow the hook, and I've never caught one on anything but live bait.