Agonomalus proboscidalis is a fish in the family Agonidae (poachers). It was described by Achille Valenciennes in 1858, originally under the genus Aspidophorus. It is a marine, polar water-dwelling fish which is known from the northwestern Pacific Ocean, including northern Japan, the Sea of Japan, and the Sea of Okhotsk. It is known to dwell at a depth range of 20 to 102 metres (66 to 335 ft). Males can reach a maximum total length of 20 centimetres (7.9 in). A. proboscidalis is a commercial aquarium fish.