Barnacle-, Signal- and Worm-Blennies are members of the family „Chaenopsidae“. These fish are superficially quite similar to members of the goby and dragonet families, as well as several other unrelated families whose members have occasionally been given the name "blenny".
The family is strictly tropical, ranging from North to South America. There are 14 genera and 90 species represented, the largest being the Neoclinus blanchardi at 30 cm in length; most are much smaller. With highly compressed bodies, some may be so elongate as to appear eel-like; chaenopsids are scaleless and lack lateral lines. Their heads are rough and may be armed with spines. The habit of taking up home in abandoned worm tubes has earned some species in this family the name "tube-blenny". At least one species found in the Caribbean is known to form a symbiotic relationship with stony coral. Many will also inhabit empty clam shells, which also serve as nesting sites; males are known to guard the brood. Some species have dorsal fins which are significantly higher towards the head, explaining the moniker "flagblenny". Crustaceans make up the bulk of the chaenopsid diet.