Identifying a few critters - can you help?

[ferret]

the 1st photo looks like a cowrie

[Myka]

The second photo is Spirorbid worms. They are beneficial filter feeders. I also think the first one is a Stomatella. Does it look like the photo with a small semi-flat shell on it's back?

[newreefer_59]

Thanks!!

[Bloodasp]

i have 5 of those suddenly showed up 4 months after my tank had been set up all different color.

[Myka]

Stomatellas will breed in the reef too. Their population will flourish and fade according to how much food is in the tank. Nice to have a self-adjusting clean up crew.