The Heterenchelyidae or Mud eels are a small family of eels native to the Atlantic, Mediterranean, and eastern Pacific. Heterenchelyids are bottom-dwelling fish adapted to burrowing into soft mud. They have large mouths and no pectoral fins, and range from 32 centimetres (13 in) to 149 centimetres (59 in) in length. There are currently eight recognized species in the two genera that constitute this family.