"if you do get a betta, 2 small corys" said Emg.
I totally agree!!! I have a 2.5g and a male betta and 2 dwarf spotted corys and they are so happy there. I had an underground filter and don't recommend it for such a small tank. I got an in tank filter from Petco that fits perfect in the small tank suction cupped to the back of the tank.
The betta gets the few flakes (which he only needs per day so he won't get fat, mine will eat everytime I feed him if I let him!!) and the corys clean up the food from the bottom and keep it real clean!!!!
My 3yr old when we got the fish, now to be 4 in May, just loves our fish. He calls them his fishy friends!! (We also have a 20g with 13 fish in it, he doesn't have and couldn't keep up anyway, with names for all of them.) When we leave the house he says goodbye to the Betta named Jr. and the corys named salt and pepper, and he says to the others "Goodbye fishy friends" How cute!!
It has also began to teach him a bit about life and passing. (We had the goldfish in the bowl and I don't have to tell you how that turned out)
Good luck with and most of all patience and have fun!!