What is this critter? Is it good or bad?

[tate1]

I have these critters in our aquarium. They breed like crazy. They look like a snail/slug with half of a clam shell on their back. I was wondering if they are good or harmful to aquariums. Just need a little help finding out what they are. Any help is greatly appreciated.

Thanks.

[Richard]

Stomatella snails. They are good algae eaters.

[tate1]

Thank you.

[SoLiD]

They will also reproduce quite fast if given the right conditions.

[tate1]

Can you please remove this ad. Thank you.

[FSU]

no reason to remove it. It helps other people with the same critter in their tank that don't know what it is.

[tate1]

Makes sense. I wasn't thinking. Thank you.