Piranhas are aquatic enemies that can be found in pools of water in the Jungle, and rarely in the Ice Caves when liquid water generates. They can be dealt with by whipping, projectiles or simply draining the water in which they swim by blowing up the walls with a bomb.
When they have nothing to hunt, they will be seen casually swimming back and forth horizontally in the pools they spawn in, but if any human character (such as a Spelunker or a Caveman) enters the water, they will immediately attack them, but will ignore Damsels.
As they cannot leave the water and are tricky to fight within it, it is often best just to simply avoid the Piranha-infested waters, rather than dive in and fight them.
Remember that water resistance reduces a Spelunker's velocity, so you cannot stomp enemies underwater. If you make contact with a piranha, even from above, you will take damage.
- A piranha stunned by the Camera will survive its pool being drained of water, hovering in mid-air until it recovers from the stun (at which point it promptly dies).
- This also happens if the water is drained while the piranhas are actively chasing the player in the water, in which case the piranhas will remain above the water, unable to enter it until the player leaves and they die.
Piranhas are a common enemy in the Jungle. Up to four may be generated randomly in any body of water.
They are the smallest enemy in the game, but can be one of the deadliest if encountered in a group. They are a guaranteed spawn on a Flooded Cavern level, along with the shoal leader, Megamouth.
By themselves, Piranhas are not hard to deal with. They die in one hit from the whip or any projectile. Note that Piranhas (like any enemy) can not be damaged by jumping if the Spelunker jumps while underwater, but it is possible to jump from outside the water to stomp on and kill a Piranha swimming near the surface. They will swim horizontally across whatever body of water they are in, and will only move vertically to chase you once you've entered their pool. Usually, one Piranha can be dodged by waiting for it to swim to the ledge closest to you then jumping in and quickly exiting the pool. Multiple Piranhas are a different story, especially on the rushing water level (where there may be 20+ of them generated in the river). In groups, Piranhas become deadly if they are able to touch you, easily doing multiple hearts worth of damage instantly. In a normal pool, you can simply bomb or undermine the pool, which will drain the body of water, instantly killing any fish exposed to air (any Piranhas that die this way leave behind skeletons which can be picked up and thrown). In the rushing water level, you must deal with them either with a gun or extremely clever use of the whip.
There are also skeletal Piranhas on the Restless Dead level. Skeletal Piranhas are exactly the same as regular ones for all intents and purposes. The only difference is that skeletal piranhas do not drop blood when killed.