I got a plastic half-barrel from Home Depot (not sure how many gallons) and found a Jack Daniels half-barrel (real thing, reeks of whiskey) at Lowe's. The one from HD is bigger than the similar ones at Lowe's and fits just inside the whiskey barrel with maybe 1" of space around the outside edge. The wood barrel is about 3 inches taller than the plastic one, too, so it's a little extra protection against jumping.
I just got done sealing the wood barrel with urethane yesterday. I have to drill a few small holes near the bottom for drainage (in case it rains). I plan to fill the extra space with pea gravel and a layer of potting soil so I can plant some ornamental grasses in there - something tall and thick for further insurance against jumpers.
When it's done I'm putting the Betta patoti that I got from Sam in there.
I wanted to do a 100 gallon stock tank but the hubs wasn't having it - something about a yard full of stock tanks looking "white trash" LOL. Instead we're hipsters with a pond with less water for more money made out of a "reclaimed" whiskey barrel.