Could you please help me ID this?

[Steve123]

Hey guys,
I'm quite new to salt water tanks. Over the last week I've noticed a worm/grub/critter in my tank. They only appear after my tank light has been on for 6 hours and they hate the light. When light is shone on them they move. Pictures are attached. Are these bad for my tank?

 

[JGT]

Looks like Stomatella. Good herbivores.

 

[IKD]

Agree, stomatella snails. Great hitchhiker

 

[Steve123]

Thanks very much, that's good to hear!