Do they eat plants, and are there different species? I have noticed
that they vary quite a bit in their coloration and are sold
differently based on color - are they still the same species?
Aquarists seem to prefer the red ramshorn snail, is it a particular
species or just a pretty color?

I'm looking into these and other snails as possible inhabitants for my
heavily planted tank as MTS have miserably failed.

Thanks for your time.