upgrade would be needed eventually, but the setup would work with a gar and a few bichirs (or vice versa or a combo). don't go with a shortnose though, as they are too skittish of a species in most cases; go with a Florida/spotted gar--
--solomon
make sure the tank's got some decent width on it, as gars neeed quite a lot of turning space. there's no need for a "special" set-up, but gars do appreciate floating plants and bichirs need their holes and such to hide in. if you're getting many bichirs you'll need more hides to prevent fighting. long, thin pieces of driftwood break up territory nicely and if done right, adds a natural look to the tank. hope that helps.