Silver Dollar Breeding Guide

Breeding the silver dollar (Metynnis argenteus): a prolific group-spawning egg scatterer; sexing, the shimmying courtship, scattered eggs over fine plants and rearing fry.

Overview

The silver dollar, Metynnis argenteus, is a prolific, group-spawning egg scatterer that shows little if any interest in its own young. Sexual maturity sets in when the fish grow to around four inches, though this is variable.

Sexing

Males develop prominent black spots and deeper red fin coloration during breeding, while females are marginally larger overall, reaching about five to six inches. These breeding-condition differences are the most practical sexing guide.

Conditioning

As a herbivore that also takes animal matter, the silver dollar should be conditioned on a varied diet of dried foods, vegetables and fruit alongside live or frozen items. A healthy shoal kept under optimum conditions comes readily into spawning condition.

Breeding Setup

Provide fine-leaved plants for the eggs to scatter onto. Because the eggs are non-adhesive and fall, breeders commonly place marbles on the tank bottom so the eggs drop between the gaps where they can develop out of reach of the adults.

Spawning Behavior & Trigger

Males become active first and spar while the females observe. The fish then scatter eggs among fine-leaved plants and directly onto the substrate during a characteristic side-by-side, shimmying courtship. Under optimum conditions, courtship and spawning in a healthy shoal often become a daily activity.

Egg & Fry Care

The species shows no parental investment and little interest in its young, so the eggs are left to develop among the plants or marbles after the adults have spawned, away from the foraging adults.

Common Challenges

The silver dollar is a large fish that actively consumes live aquatic plants, so the spawning medium must withstand grazing, and a very large tank is needed to keep a shoal in spawning condition. Protecting the scattered eggs from the adults, typically with marbles or dense fine plants, is the key practical concern.