Note 2416 — BOOK IX. THE NATURAL HISTORY OF FISHES.
John Bostock translation
He would almost seem to imply by this that they feed upon shell-fish: but Hardouin has a note to the effect, that Pliny does not mean that they live on shell-fish, as it would be impossible for them to break the shell to devour the fish within, but only that they have the same flavour as shell-fish. But query as to this explanation.