poacher, (family Agonidae), any of the marine fishes of the family Agonidae (order Scorpaeniformes), a group of approximately 50 species that also includes alligatorfishes, sea poachers, and starsnouts. Poachers live in cold water, on the bottom, and are found mainly in the northern Pacific Ocean. They are small fish, measuring about 30 cm (12 inches) or less in length, and are distinguished by the bony, often saw-edged armour plates covering their body.
Notable species include the sturgeon poacher (Podothecus acipenserinus), a large, common, northern Pacific poacher, and the hook-nose, pogge, or armed bullhead (Agonus cataphractus), a small fish common in northern Europe and one of the few poachers found outside the Pacific. The various species are of little commercial value.