Can you identify this?

[Bectan01]

His has come up in my 10g nano reef - it has tripled in size in about two months. What is it?

 

[Faucett]

I'm gonna guess and say it looks like a sponge

 

[carey]

The little purple branches look like some kind of macro algae to me.

 

[Bectan01]

Thank you for your replies, yes - I've never seen anything like it? It seems to be branching and has bright orange tips. As I said, fast growing... Whatever it is I like it so I hope it's not harmful!

 

[Sniperhank]

It's a macro algae. It'll color up more as it grows.