What is in my sump?

[Macsreefs]

Recently I bought a new tank from someone at my LFS (they are very trusted there). I kept everything in it water sand everything it was a short drive home and later that night after setting it up I saw a sexy shrimp in there on top of the carbon bags. So when I got home from work I went looking for him and I noticed something in the back of the sump and can’t figure out what it is. It is big maybe half the size of my hand and hard.. looks porous and seems a bit slimy it started growing on the heater back there. I’ve been searching and searching and can’t seem to find anything, unless this is a world record pineapple sponge…. Any ideas? Is it harmful?

 

[Katrina71]

Sponges. Good guys

 

[Macsreefs]

Sponges. Good guys

I haven’t found one online that big yet like a clump only a bunch of little guys or like a web of them.

 

[Katrina71]

Is it yellow when you have a light on it?

 

[Macsreefs]

Is it yellow when you have a light on it?

No, it seems to be more white than yellow.

 

[Katrina71]

Not sure of the exact type, sorry

 

[ISpeakForTheSeas]

Yeah, those are definitely sponges - harmless filter-feeders.

Sponge ID can be really tough, and you may have different kinds of sponges in the photos. I can't see the first one well enough to even really guess, but the ones growing on the heater may be a Clathrina species.

sponge ID can be incredibly difficult, with some sponges needing a microscope or DNA test to be ID'ed

Anyway, here’s a good Sponge ID resource for anyone who’s interested- as mentioned, though, sometimes DNA is the best indicator for telling sponges apart:
https://www.fao.org/3/i7773e/i7773e.pdf And, here’s a decent example of why sponge ID by non-microscopic sight is not always reliable:
https://www.researchgate.net/figure...rating-variations-in-shape-and_fig6_248716402