The Angler Fish has appeared as a boss in two "Legend of Zelda" games on the GameBoy.
Links AwakeningLink encountest this bos in Angler's Tunnel, the fourth dungeon in The Legend of Zelda: Link's Awakening. 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, these attacks are all very easy to dodge. Link fihts the Angler Fish under water. It's vulnerable point is the esca (the fleshy growth resembling a lure) that hangs from its forehead. Link can slash the esca with his sword, or he can use his bow or bombs. This is a very weak boss, and it requires almost no strategy.
Oracle of Ages
The Angler fish makes another appearance in The Legend of Zelda: Oracle of Ages. Although Link encounters this mini-boss in Jabu-Jabu's Belly, the batle is fought on land. The Angler Fish will either jump on top of Link or spit bubbles at him. Link uses his Seed Shooter to bring it down, and then strikes the esca with his sword. After taking some hits, the fish will repuff and bounce around, shooting bubbles. After several repetitions of this pattern, the Angler Fish will explode.