Angler Fish

The Angler Fish is a boss and a mini-boss in and, respectively. It strongly resembles its namesake.

Link's Awakening
In Link's Awakening, Link encounters the Angler Fish in Angler's Tunnel, the fourth dungeon. Angler Fish is the Nightmare guarding the Surf Harp. It can use a ramming attack, fling enemy fish at Link, and drop debris on him.

Link fights it underwater. Its vulnerable point is the esca (the fleshy growth resembling a lure) that hangs from its forehead. Slashing rapidly with the sword is most effective, but the Bow and Bombs will work as well. This boss requires little strategy to defeat and, if Link is quick enough, can be killed even before it has a chance to attack.

Angler Fry also appear during the battle. They do not actively attack Link, but swim around the area aimlessly, hurting him if he touches them. They require one hit from the sword to defeat.

Oracle of Ages
In Oracle of Ages, the Angler Fish appears as a mini-boss in Jabu-Jabu's Belly, and is fought on land. The Angler Fish will either jump on top of the young hero or spit bubbles at him.

The best strategy is to shoot it with the Seed Shooter to bring it down, then strike its esca with the sword. After taking some hits, the fish will re-puff and bounce around, shooting bubbles. After several repetitions of this pattern, the Angler Fish will explode.

Trivia

 * If the Angler Fish in both Zelda games are the same as real-world Anglers, then both the Anglers Link fought were females, as males are small minnow-like fish without a lantern.