Any idea what this is?

PolypPocket

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Is it a bacteria? Sponge? I know it’s probably not algae but I didn’t know which category to post this in.

This is a new tank going through a tough cycle (had a big die off event). Ammonia is finally starting to come down as of today but still high at 4.0 ppm (was at 8.0). I’m only adding this info in case it’s relevant.

It’s mostly contained to this rock but there are a few other tiny spots I noticed on a couple of other rocks.

No fish no corals, only what came on the live rock (random tunicates, polyps, etc).


20260708_235601_EBCFD316-E5EE-4D7E-B155-DAE7EB9EABEA.png


20260708_235601_F0B5B3E5-6474-4141-8779-40498769D686.png


20260708_235601_D98A0EB6-7691-43B1-9FD9-B256EAABED44.png
 
Agree, appears to be some type of Leuconoid sponge. When we typically think of sponges we envision the barrel or vase like sponge. The leuconoid sponges are NOT this type of sponge. They appear to be an amorphous tangled mass when in fact they do have the typical sponge morphology on close examination.
 
Agree, appears to be some type of Leuconoid sponge. When we typically think of sponges we envision the barrel or vase like sponge. The leuconoid sponges are NOT this type of sponge. They appear to be an amorphous tangled mass when in fact they do have the typical sponge morphology on close examination.
Thank you! I’m glad it’s not something “bad”.
 
Sponge, but a really neat looking sponge
 

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