Makapu'u tidepool, Oahu 

Hanauma Bay, Oahu, 2 feet

Sharks Cove, Oahu, 10 feet

Common in the surf zone living in empty worm snail tubes.  Base color green in females and gray with reddish brown in males.  Attains 5 inches.  East Africa to Hawai'i and French Polynesia.  Formerly known as Istiblennius gibbifrons.