What's this?

[reefgirl189]

Found three of these weird things in the reef tank today. They seemingly showed up from nowhere.

I can't get a very good picture but it looks almost exactly like a spider's nest. Like a web wrapped around a spider's prey that he's saying for later, only with a small hole going through it. At the end of the hole it protrudes out slighty, acting like a mouth as all three I can see were facing that way towards the light.

So I harrassed one and it didn't do a thing and didn't move much if at all. The only thing I can think of is that I fed a few mysis shrimp to the crabs and shrimps and that a few were never found and they decayed or something but to be perfectly honest these white cone ball spider things are much to large to be one decayed shrimp, and why would they all be facing the same direction, towards the light?

Can anyone give me a clue?

Water parameters:

Salinity 1.025
NH4 0ppm
Nitrites 0ppm
Nitrates <5ppm
Calcium 380
pH 8.32
Temp 80.2

Last water change was 8 days ago, 20% changed out.


No fish, only a few hermit crabs and peppermint shrimp and one cleaner shrimp. Variety of soft corals. Tonnes of pods and feather duster worms.






In this last pic the weird thing is in the very middle of the picture, right underneath the lowest part of the hammer coral.

[Cal_stir]

looks like a small sponge, harmless filter feeders, pics are pretty blurry though

[Mandosh]

Hard to see really, but based on your description and what I get from the pics they're most likely scypha sponges.

[reefgirl189]

I googled scypha sponges pictures and I'd say you are probably right.

Thanks guys