White crowned cone critters

[rsumner]

I noticed a few of these in my sump last week and after I gave it a good scrub-down, they are now a part of my display with numbers nearing 20 now. They are a cone shape with the base being the thickest. The largest of the species have what seem to be a filtering crown on the top where there's a hole.

I would appreciate any feedback and if I should start manual removal of these things as they seem to be reproducing.

 

[Palyzoa]

Pineapple sponges, good filter feeders