Also known as Bighead Silver Dollar.
Found in schools, usually close to the surface, of rivers.
They feed on algae and plants.
Length - 18cm
Depth - ?m
Widespread South America
Popular Aquarium fish.
Related to Piranha's but these are strictly vegetarian!
Piranha's have a fearsome reputation (because of James bond 007) as a voracious predator that can strip flesh off bones in minutes, although they have razor sharp teeth they are in fact quite timid scavengers. Ref: https://www.fishbase.se/summary/11937