Need to identify snails

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Seems like I have 2 different types of snails in the tank. All multiply fast. I did not introduce them on purpose. I have artificial plants. The only thing I can think of is they came from frozen bloodworms (is this possible?) or sand (is that possible?). At any rate, they move quick, stay small, bother no one and really help clean up, so I'm just leaving them alone for now. Some look like pond snails from what I can tell compared to images on the internet. Not sure about the other one. It seems to look exactly the same, but have teeny, tiny speckles on it. Maybe someone can help me identify, please, so I know. Thanks.

Attaching the best photos I could get of a couple.

 

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Realize I am on Saltwater and Reef identification and cannot figure out how to move this post yet. Sorry, as I did not realize. Trying to figure it out now. Thanks.