Unwanted sponge help

[new_world_disor]

Got this big oll' sponge growing accross my mushroom rock. Any ideas what it is? Is it bad? (other thsn using up nutrients) and how do I get rid of it?

http://uploads.tapatalk-cdn.com/20160123/3e551ad26c4d2689f3af48728d4d1449.jpg

http://uploads.tapatalk-cdn.com/20160123/5a3523a8be1d9f2d4e3c5512dd479acd.jpg
Also just noticed this tucked away in shrimp cave.

Thanks

[Moeshi]

They are beneficial to your aquarium. If you want to kill them, increased light and flow can decimate them in days.
They are generally a sign of a healthy tank. :)

[new_world_disor]

Ah they can stay there then. Not effecting anything. Thought they might take over the tank