Swordfish eat squid, menhaden, mackerel, bluefish, silver hake, butterfish, and herring. It slices at its prey, but a swordfish will never stab its food. We see most swordfish at night, when they come up to fish, but we have also seen them during the day. Swordfish are prey to killer whales, blue marlins, sailfish, yellow tuna, dolphin fish, and humans (because they harpoon swordfish).
