No, I'm not planning on doing this anytime soon! Just wondering if it's possible? You hear of gars as being pond fish mostly. I guess that's just because it would have to be a reallly big (custom?) aquarium?

Yeah, to have a gar in a tank you'd need what's commonly called a 'monster fish tank'. I suppose young ones could live in a large tank for awhile (but I don't know how fast they grow) but eventually it would need a custom made tank.