Some of the snails I have are a weird green color. They're just regular old MTS and ramshorns, nothing spiffy, but, in the one tank I've been noticing a green color to some of my snails. It's almost as if their bodies are green (but their feet aren't). This is my planted tank, but I honestly don't think they've been snacking on plants, they're usually on the ground and occasionally on the glass, but rarely if ever on my plants.