Piranha

The Piranha are enemies that can be found in water pools of the Jungle and Cavern layers. They have an increased spawn rate in the Jungle. They swim in a straight line left or right until hitting a wall, where they flip directions. They will swim towards the player if they are submerged in water; otherwise they pay no attention to the player. It moves its tail back and forth and swims in a slight zig-zag.

If a Piranha is outside of the water, it will flop around wildly, making it dangerous to approach.

When your world enters Hardmode, Piranhas become mostly overridden with Angler Fish, however; piranhas will still be common in Jungle biomes.

History
Piranha Piranha Pirája Piranha Piranha Пиранья 食人鱼