The snailfish (Agonopsis chiloensis) is a fish in the family Agonidae (poachers). It was described by Leonard Jenyns in 1840. It is a subtropical, marine fish which is known from the southeastern Pacific and southwestern Atlantic Ocean, including Chile, Patagonia, and Argentina. It is known to dwell at a depth range of 3–400 metres. Males can reach a maximum standard length of 12.5 centimetres. A. chiloensis is preyed upon by Cottoperca gobio, imperial shag, Pinguipes chilensis, and the narrowmouthed catshark. It is of no commercial interest to fisheries.