The Hydra is a three-headed sea serpent that's elusive in Dino Island based on the Lernean Hydra. It's the last fish you'll encounter after the Flaming Coelacanth. It takes about fifteen to fourteen slices to cut it into half, and it is worth 500 coins! However, it can be drilled in a hit. Although the Hydra is listed as a fish, it is actually a reptile.