Hello kcdavebob...
and welcome to Aquaria Central!
One suggestion I have for you, if your son isn't too interested in any of the fish mentioned, you could always go the african dwarf frog route. Just make sure they're they dwarf variety, not clawed. Clawed frogs would get to big for your tank. I setup a tank for my boyfriend a while back... a 3 gallon with 2 dwarf frogs and a betta. Good luck!
and welcome to Aquaria Central!
One suggestion I have for you, if your son isn't too interested in any of the fish mentioned, you could always go the african dwarf frog route. Just make sure they're they dwarf variety, not clawed. Clawed frogs would get to big for your tank. I setup a tank for my boyfriend a while back... a 3 gallon with 2 dwarf frogs and a betta. Good luck!