Is a freshwater snail a carnivore herbivore omnivore?

I would say it is a herbivore, because they would probably eat the algae in the pond, but some might be carnivores or omnivores, so your best bet is to just look online.

it would be a carnivore

Not all snails are herbivore nor are they carnivores. Carnivore snails can drill into a herbivore snails shell and eat them! they're scavengers

Snails are herbivores. A snail eats mostly plants and most living leaves and plant barks. They also eat paper and cardboard believe it or not. That and limestone and chalk to help their shells stay...

An omnivore. They tend to eat lots of salmon, as well as grasses and other plants.