you mean peppered cory cats right?
hmm you could within reason keep 2 in there, BUT only when they're small, and this is not ideal, they need to be in schools of 4+, and eventually they WILL grow out of that tank. cories are fairly active nosey little fish and like to get into everything with lots of ground space to dig around in, you could keep some there for a temporary measure, but really they need 10 gallon+.
p.s. corys are fine with Bettas, as long as you don't get a betta like mine in my avatar who's hobby was to take chunks out of my albino corys.