Fish have developed some interesting ways of catching prey, but it is unlikely that any fish hunting for food can match the methods of those that angle for other fish.
A good example is the deep-sea angler fish, which fishes for other fish with a natural pole or line that grows out of its head. The pole, called the illicium, is actually the first ray of the creature’s dorsal fin and can in some species be more than 80 percent of the length of the fish itself. At the long stalk’s end is a phosphorescent luminous blob of “bait” called the esca. Luminous bacteria cling to the blob, attracting other fish toward light that they mistake in the dark depths for a luminous shrimp or similar prey. Before the other fish have a chance to snap at the bait, the angler fish opens his mouth, creates a suction that pulls them in, and swallows them.
The Pacific frogfish has strands that resemble fishing lines growing out of its head. The lines look like swimming worms, and when other fish nibble at them they are caught on the barbs or hooks of the line and are gobbled up by the frogfish.
One species of angler fish (Linophryne arborifer), which lives 1,600 feet down, sports a luminous “lantern” growing from a stalk at the top of its head that lures food toward its open jaws. As soon as its prey gets within range, the huge netlike jaws close around it. Another species Huplophryne deep-sea angler, is encased in a jelly that reduces its specific gravity and enables it to float better.
Angler fish have teeth on the floor of the mouth as well as in the jaws, and they commonly swallow fish three times their size, digesting them in their distended stomachs. A large relative of the genus Lophius grows to four feet long and lives camouflaged on the ocean floor, its dorsal fin fishing rod protruding from its head to attract prey. The goose-fish, as it is called, will eat almost anything it can close its jaws on, including diving birds. One specimen, caught many years ago, had seven ducks in its stomach.
The archerfish shoots down prey such as insects flying just above the sea’s surface by spitting water at them