[JustOneMore20]

I agree with Nelson (Gourami ^). That tank will not work for any fish that is schooling, a fast swimmer, or anything that swims around. A betta should be fine, as they are pretty slow generally......and shrimp would work, although you'd be limited on numbers. Those tanks aren't really good for much IMO....and I don't like them because I know people stock them incorrectly.

For a barb only tank, you are looking at atleast a 30g (3ft) for 1 species or more like 55 to 75g for more than one species of Barb. Most Barbs get big and they are very active and schooling, meaning that atleast a 3ft tank is recommended for most of them.