Ectopleura larynx is a colonial, athecate hydroid (family Tubulariidae) widely distributed in shallow, wave-exposed rocky shores and artificial structures across the North Atlantic and North Sea. Morphologically, it forms dense, pinkish tufts characterized by unbranched or sparingly branched corneous hydrocauli that support large, solitary hydranths. Each flower-like hydranth features two distinct, concentric whorls of pale pink to reddish tentacles: an outer ring of long aboral tentacles and an inner cluster of shorter oral tentacles surrounding the mouth. Characterized by a direct life cycle, E. larynx lacks a free-swimming medusa stage; instead, it develops fixed gonophores (sporosacs) that release ciliated actinula larvae directly into the water column. As a notorious marine biofouling organism, this species exhibits exceptional capabilities for rapid recruitment and space competition, frequently infesting coastal aquaculture infrastructure, ship hulls, and marine energy installations.