White Circular Critter with Ruffled Edges

[jefra]

I checked several reference posts/sites and wasn't able to find anything that resembles this. There's about three of them in my sump. White, circular with ruffled edges. Appreciate any help!

 

[Lukas75]

It's hard to tell from the picture, but it looks like limpet to me. The white center part is the foot while the "frill" is actually the underside of the shell. If you look at it from the inside is it a hard shell over it? If so they are harmless in my experience.

 

[Kanshi]

I checked several reference posts/sites and wasn't able to find anything that resembles this. There's about three of them in my sump. White, circular with ruffled edges. Appreciate any help!

I had one. From what I have found out, its a polyclad flatworm.
Bad guy!

 

[ScottR]

+1 limpet

 

[ScottR]

Also I see what looks like naididae on the glass.

 

[jefra]

Thanks all! I've been hoping to get limpets for a while now.

 

[Softhammer]

Definitely limpet, good dudes to have.