Fish
Silver Dollar Fish
Metynnis argenteus
Flashing like a handful of shining coins, a school of silver dollar fish moves together through Amazon basin waters, a peaceful, plant-eating relative of the far more infamous piranha.
Overview
The silver dollar fish, Metynnis argenteus, is a Least Concern fish found across rivers and flooded forest throughout the Amazon basin. Its flat, coin-shaped silvery body, schooling behaviour, and surprising kinship with piranhas and pacus make it one of the more visually distinctive and ecologically peaceful members of its fish family.
A gentle relative in a fierce family
Despite belonging to the same broader family as the predatory piranha, the silver dollar fish has taken an entirely different path, feeding on plant matter and schooling peacefully rather than hunting, a reminder that close relatives can lead very different lives.
Status
Least Concern, remaining widespread across suitable river and flooded forest habitat throughout the Amazon basin.
Silver Dollar Fish: common questions
Why is it called the silver dollar fish?
It shows a flat, round, silvery body that closely resembles a shining coin, a resemblance that gives the species its common name.
Is the silver dollar fish related to piranhas?
Yes, it belongs to the same broader fish family as piranhas and pacus, though unlike the predatory piranha, it feeds mainly on plant matter.
Does the silver dollar fish live alone?
No, it is a schooling species, typically moving and feeding together in groups rather than remaining solitary.
What does the silver dollar fish eat?
It is a herbivore, feeding mainly on aquatic and overhanging plant matter.