Anyone know what this critter is?

[WrasseLass]

I just cleaned a bunch of algae out of my sump and found these critters that look like tiny smooth (no hair or bristles that I can see) caterpillars. I’ve never seen these. In the photos they look flat, but they aren’t. They are nice and chunky. Any help on an ID is appreciated!

 

[Rach77]

Do these caterpillars move?? They look like pineapple sponges from the distance, and they like to grow in the algae

 

[crazyfishmom]

They look like little stomatella snails… do they have hard tops or are they squishy?

 

[WrasseLass]

Do these caterpillars move?? They look like pineapple sponges from the distance, and they like to grow in the algae

Yes, they move. They sort of inch, like a caterpillar or slug.

 

[WrasseLass]

They look like little stomatella snails… do they have hard tops or are they squishy?

They’re squishy. But they are also super tiny. Could they have shells that haven’t completely hardened yet?

 

[Sphyrna_gal]

can't make out the photo but maybe this article will be helpful?:

https://reefs.com/pest/

 

[BristleWormHater]

Probably flatworms of some kind, remove them most do more harm then good.

 

[ISpeakForTheSeas]

They’re squishy. But they are also super tiny. Could they have shells that haven’t completely hardened yet?

Any chance you could get closer up pics?

 

[WrasseLass]

Yep. Turned out to be stomatella snails. Think I’ll keep ‘em! Thanks everyone!