[3][4][5][6][7] Blenniformids are generally small fish, only occasionally reaching lengths up to 55 cm, with elongated bodies (some almost eel-like), and relatively large eyes and mouths.

As generally benthic fish, blenniiformids spend much of their time on or near the sea floor; many are reclusive and may burrow in sandy substrates or inhabit crevices in reefs, the lower stretches of rivers, or even empty mollusc shells.

[3][4][5][6][7] As far as predation, blennies depend on a secretive lifestyle, hiding on the sea floors in shallow water, with cryptic coloration.

[9] True blennies are widely distributed in coastal waters, often abundant and easily observed which has made them the subject for many studies of ecology and behaviour.

It is thought that the splitting of the Tethys Sea by the formation of the Isthmus of Panama combined with Pliocene warming of the climate may have been important factors influencing the evolution and biogeography of the Blenniiformes.