Mochioka, N., Iwamizu, M.

Marine Biology 125, 447–452 (1996). doi:10.1007/BF00353257

Diet of anguilloid larvae: leptocephali feed selectively on larvacean houses and fecal pellets.

Proposes that “that the peculiar, large, fang-like teeth of leptocephali are used for feed- ing, and evolved to pierce and grasp the mucous houses of larvaceans”. Found houses and fecal pellets that may be from O. longicauda.