What is this growing on my rock?

[Drew11]

Any ideas? My nitrates were fairly high when I tested my water the other day... Around 60ppm, so I just did about a 20% WC. Not sure if its a form of algae or what?

[thegrun]

It looks more like a bacteria mat or sponge.

[cloak]

Is it hard or soft? Does it branch out? A Foraminiferan came to mind first.

http://www.lionfishlair.com/hitchhiker/hitchhiker.shtml

[Drew11]

Is it hard or soft? Does it branch out? A Foraminiferan came to mind first.

http://www.lionfishlair.com/hitchhiker/hitchhiker.shtml

LOL I didn't want to touch it. It doesn't look like it moves much in the flow of my tank but that could be because it's so small or the current isn't as strong there. It looks as though it is extending a bit outward.

[sailorinokc]

It looks like a sponge I have something similar in my overflow.

[Drew11]

Here is a picture I took today. It's growing and spreading! Is it good or bad? Leave it?

[accordsirh22]

looks like a sponge, might as well leave it