Ophidiiformes

Ophidiiformes: Pelvic fins when present, inserted at level of preopercle or farther anterior (mental or jugular), zero to two soft rays in each, and occasionally with a spine; base of dorsal and anal fins long, extending to and usually joined with caudal fin; nostrils paired on each side; dorsal and anal fin pterygiophores more numerous than adjacent vertebrae (the ratio being about 1.8:1).
 * See Fishbase.

Families in this order:
 * Aphyonidae
 * Bythitidae
 * Carapidae
 * Ophidiidae
 * Parabrotulidae