My 3 year old male betta, Picasso, was looking lethargic and depressed for a couple weeks and I began to worry. I bought him a more spacious tank and added 2 apple snails to accompany him. I was surprised to see that after a couple days, he began to swim and became more energetic. He seems happy and he's always swimming wherever the snails are. Now he exhibits all the signs of a healthy, happy betta!
I don't think this is usual behavior for bettas to get along with snails..because my other 3 male bettas absolutely hated having snail company. I guess Picasso and his snail friends have a special bond. It can happen.