Actions/Abilities/Traits: (Pathfinder 2e)
Ability
Blood Scent
The piranha swarm can smell blood in the water from up to 1 mile away.
Ability
Feeding Frenzy
2 circumstance penalty to their Reflex saves against Feeding Frenzy while this damage continues, as the piranhas' frenzy increases in intensity when they smell blood.
Trait
Animal
An animal is a creature with a relatively low intelligence. It typically doesn't have an Intelligence ability modifier over -4, can't speak languages, and can't be trained in Intelligence-based skills.
Trait
Aquatic
Aquatic creatures are at home underwater. Their bludgeoning and slashing unarmed Strikes don't take the usual -2 penalty for being underwater. Aquatic creatures can breathe water but not air.
Trait
Swarm
A swarm is a mass or cloud of creatures that functions as one monster. Its size entry gives the size of the entire mass, though for most swarms the individual creatures that make up that mass are Tiny. A swarm can occupy the same space as other creatures, and must do so in order to use its damaging action. A swarm typically has weakness to effects that deal damage over an area (like area spells and splash weapons). Swarms are immune to the grappled, prone, and restrained conditions.
Immunity
precision
swarm mind
Perception
blood scent
low-light vision
scent (imprecise) 100 feet
Resistance
bludgeoning 5
piercing 2
slashing 5
Weakness
area damage 5
splash damage 5