The colorful bits on the red encrusting sponge are tunicates. Tunicates or sea squirts actually have a central nervous system. The transparent tunicates with rings in this image are singles; the black, pink and yellow tunicates are colonies. The white I was told is a kind of coral, but I'm sorry to say I don't yet know more than that. For other tunicate images see Gold Tunicates and Green Nudibranch Over A Tunicate.
I think this image is best no larger than 9 x 14.