Omobranchus anolius-male oyster blenny.

This male omobranchus anolius, as with most, was hiding in an old barnacle, so bottle over barnacle, barnacle off the rock for pic.
In this pic you can just make out this guys blue markings as it hides in an old barnacle, now it lives at my place in a tub, its best, they like to jump out if they can.

At his home


Put into a container for a pic, then back where it came from, they drop their colours a bit when in stress.