what is this?

[kelrn98]

I noticed this in my sump a few months ago and didn't think much about it, it was much smaller then. Now it is covering a softball size piece of LR in my sump. I don't know much about nonphotosynthetic creatures, but I figured this must be one as it is thriving in my sump which is illuminated by a simple energy efficient bulb you buy at lowes.

<a href="http://s682.photobucket.com/albums/vv190/kelrn98/?action=view&current=100_4095.jpg" target="_blank"><img src="http://i682.photobucket.com/albums/vv190/kelrn98/100_4095.jpg" border="0" alt="yellow sponge?"></a>

 

[stunreefer]

Appears to be a sponge of some type, could be non-photosynthetic or photosynthetic. Some photosynthetic sponges require very little light IME, and if the light is sufficient to grow your Chaetomorph it could also grow some sponges.