Hi
First up nice Betta I love the Blue ones.
Next I think you need a few more plants including some floating ones, I find Indian Fern ( Water sprite ) is the best floating plant for Bettas.
As for snails, It may or may not work, If he is aggressive expect bitten off Antena on the snails ( these grow back ) I have 1 snail in a tank with 4 female Bettas and I never see it move during the day he used to but the girls harrased him too much.
You are going to have to feed the snails, They cant survive on algae alone, and this presents another problem once the Betta discovers that the stuff you feed the snails tastes great he is going to eat the food. I feed my snail at night once the lights are off.
This video is of the sorority tank I lost in the floods.