Convict Blenny

Pholidichthys leucotaenia

Convict Blennies, also known as engineer gobies, are eel-shaped fish that can reach lengths of up to 34 cm. Despite their common names, they are neither true blennies nor gobies but belong to the family Pholidichthyidae. Juvenile Convict Blennies have a black body with a distinctive white dorsal stripe, mimicking the venomous striped catfish Plotosus lineatus. As they mature, this stripe transforms into a pattern of white bars or spots. These fish inhabit shallow lagoons and coastal reefs in the west-central Pacific, from the Philippines to the Solomon Islands, typically at depths of 3 to 30 meters. They are often found schooling under ledges or around coral heads, swimming in tight formations that give the impression of a single large organism. Juveniles venture out from their burrows to feed on plankton, while adults remain within their intricate tunnel systems, which they maintain by expelling debris. Divers encountering Convict Blennies may observe their unique schooling behavior and the juveniles' daily feeding excursions. They are harmless to humans and are sometimes seen in the aquarium trade. The IUCN lists them as Least Concern.