What is this?

[SABOB]

Found this on a piece of coral skeleton in my tank.Is this some kind of algae and is it good or bad?2nd pic shows a blue item on another coral skeleton.This tank is 3-4 years old ,currently having some hair algea and cyno issues.Thanks for any input.

[oceancube]

blue stuff=sponge good stuff wont hurt a thing.. green stuff not sure!!!

[abe77901]

Green stuff is a type of macro algae = good stuff..grows well

Blue stuff is a blue sponge = good stuff

Good Find!!

[blueboy]

that macro in the first shot is called codium.