Snail should be fine,
They are small, barely more than a half inch and colorful. My favorite is the bumblebee nerite--you guessed it--black and gold swirls. The larger nerites put out a lot of waste for such a small bowl. The horned nerites don't. Plus, nerites do not successfully breed in fresh water so you don't need to worry about being swamped with snails.
I have been very happy with my nerites from a guy on ebay, if you want info. Not so happy with other dealers and a dealer on this website. PM me if you want the name of the ebay guy.