Blennies are shy

Slowly drifting past a reef, a blenny slinks down inside his little rock home until only his head remains shyly out, observing me. I hover there watching him size up the situation, his little eyes darting back and forth, sometimes ducking a few milimeters further into his hole, then back out again... is it safe? not sure! yes! maybe? no! And with a quick movement, he is gone.