$40 is a good deal but get ready for a very difficult to raise fish. They are pelagic fish, they are also a rather big fish, big you can get around pelagic is much more difficult. If you manage to dwarf the fish somewhat you might be able to keep one in a tank with a big foot print. I would want a tank of about 3' by 8' foot print, how tall the tank is would not be as important as how much surface area it has. If you really want to keep the fish to it's reasonable adult size it needs to be in a pond, a large pond....