The Florida blenny is a small fish growing to a maximum length of 4 in. but a more typical length is 2.4 in. The single, continuous dorsal fin has about six spines and nineteen soft rays. The anal fin has eighteen or nineteen rays. The color of this fish is a mottled or speckled brown. The sexes differ in that the female has the first anal spine reduced in size. In the breeding season, territorial males have enlarged anal spines with associated fleshy lobes and longitudinal folds of skin. These males also grow larger than the females, have pale longitudinal markings, an iridescent blue spot at the front of the dorsal fin, an orange streak running backwards from the blue spot and orange coloring on the gills and throat.