Some controversy with otos and corys based on the tank size and they like to be in school. I personally have snails in with my betta, they are very fun to watch! But unless you have algae, you'll have to supplement they're diet with algae wafers or veggies. And don't be surprised to see some poo, I have to pooper scooper my sand:( Shrimp are really cool as well, and have very little bioload so much less messy. Downside to them is they may be seen as a snack, but that depends on the betta. You could spluge the 33 cents and see if your betta eats it, if not there are a ton of variety of brightly colored shrimp you can check out such as cherry, bumblebee, blueberry, the list goes on and on.
55 Planted Community: Tetras, Guppies, Kulhlis and 6 beautiful LadyBettas (awaiting their own tank:))
5.5: Divided: PoopyFace Tomato Nose (MaleCT), and HandyQuacks (Snail), SpongeBob (MaleVT), and Gary (Snail)
38: In Progress to be divided for 2 males, and a center sorority!
One FAT beagle Winston
3 Mischievous Cats: Bahgeera, Ballo, Gibby
One not so cuddly rabbit: Cadburry