silver dollar fish (Monodaotylus argenteus), also known as the silver finger or silver coin, from the Perciformes family, is a fresh water fish, of a medium size that is located in the rivers of South America. It is a tropical fish that is easily distinguishable thanks to the shape of its rounded body and its shiny silver scales.

Silver dollar fish

Silver dollar fish


The silver dollar becomes about 15 inches or about the size of a saucer. They are shiny silver in color and in some varieties the male will have a small amount of red on his anal fin.

Its own name indicates its appearance, round and silver, because its body is almost round and very compressed laterally. The scientific name says it all: the genus term Metynnis means "with plowshares," and the species name argenteus means "covered with silver."

M. argenteus is generally silver in color, but with slight green and blue tones in the right light. Notes of red will also appear, especially on the male's anal fin, which is rimmed with red. In some habitats, they will have small dots on the sides.

This species and its close relative Metynnis hypsauchen are known as the Silver Dollar. The two species can only be distinguished by the black spot or shoulder patch slightly above and behind each eye of M. hypsauchen.


The silver dollar fish is a very popular fish among tropical fish and can be easily seen in any aquarium in the world. It was discovered in the Tapajas River basin, a river that flows into the Amazon through Brazil. These fish are said to be related to piranhas, which also inhabit the rivers of South America.

It is a mainly peaceful species, and they are generally very sociable animals, but they tend to have an aggressive and dominating attitude especially towards smaller species, they have the same instinct as the piranha to intimidate.


The silver dollar fish spends its life among the grasses in the lush areas of the rivers, where it finds large quantities of food and protects it against predators. They form groups known as shoals, capable of collaborating to hunt larger prey or intimidate their predators.


It is an omnivorous fish, although its diet is essentially vegetarian. It feeds on herbs and aquiferous plants, it also feeds on small insects.


The small size along with its bright color make it a remarkable prey among larger birds, reptiles and fish. These are its most common predators.


Silver dollar fish can live for about 10 years and spend most of its life in the upper reaches of rivers. They usually reproduce in calm, warm and dark waters, the female can deposit around 2000 eggs.

State of conservation

Their concern is almost nil, since they are animals that, apart from being free, you can see them in thousands in fish farms, since it is a fish in high demand in aquariums and fish tanks around the world.

Relationship with humans

The silver dollar fish is one of the most popular fish in the aquariums of tropical fish collectors. It is recommended that they be the smallest fish in the tank as this will make them feel more comfortable and live happier.

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