Black Sponges

Does anyone know about black sponges. I have a pic on my profile of them. It came with my LR. I thought it was neat at first but now something on the rock releases this web like jelly stuff...It's stringy and some times collects in corners of my tank. It's released during water changes and top off. Perhaps the water flow hitting them... LFS said I could scrub them off the rock and simply get rid of them...the more I look the more I think it could be the cylindric shaped tubes growing amongst them.....

 

Sponges don't tend to release stuff like that into the water. It's more likely to be a worm or snail in the holes you mentioned.

 

Would you recommend I keep the black sponges? Do they serve any useful purpose within the tank community? They aren't great to look at, that's why I ask.

 

If you want, you can keep them. If this is a new tank, they'll likely die off anyway.

Sponges capture organics from the water, so they can be useful in your filtration if they can stay long term.

 

Well the tank is about 4 months old. I did just have a phosphate spike due to trying a different food source that wasn't being ate. Discontinued use, and a few water changes and that will be resolved. I suppose I will keep the sponges. Can't hate on them for being ugly! They're natural so I'd ate to remove them.

 

Mission, they are firm but there is a little give to them. More slimy than anything is noticeable....