Advice needed
 

I have been fighting Green Hair Algae for quite some time. The hair is starting to thin out slowly causing me to notice a neon green spider like thing in with the hair. I looks as if it is alive as the way it moves. I seems as if it has a base and the legs stream around and through the Hair algae. Anyone know what it might be, should I remove it?

Thanks

Marcus

The arms seem to be about a 1.5" long.

could be a green brittle star there marcus

I found a total of three, one seems to be a smaller version and yellow with the base attatched to the rock. The arms move all over the place.