Yeah, a one gallon tank is the minimal for one betta. He'll be fine of course in there as long as the water changes are kept up :D You cannot have any other fish unless you have 10+ gallons, or the ammonia may spike and kill both fish.
3+ gallons is where you can have bottom feeders, like snails or shrimp I believe. 5 gallons is better IMO, but acceptable in 3 as long as you keep up with the water changes and have hiding spots. Live plants are a fun thing to try out though, if it sounds interesting! :D
Last edited by Sprinkles55; 08-08-2012 at 05:28 PM.