银板鱼

Overview

Metynnis argenteus is a deep-bodied, silvery fish commonly sold under the same silver-dollar label as close relatives. It readily damages plants, prefers company, and generally suits communities of larger peaceful fishes.

Distribution & habitat

It may be restricted to Brazil's Tapajós drainage. Silver dollars are associated with densely vegetated tributaries, creating a practical aquarium challenge: cover is helpful, but living plants are also food.

Aquarium setup

An adult group requires a footprint around 180 × 38 cm or more, with length and width more useful than extra height. Keep at least five. Subdued lighting and sheltered areas help these nervous fish settle.

Even durable plants may need replacement. Soft, suitable artificial planting can provide cover where maintaining living vegetation proves impractical.

Diet & feeding

Plant ingredients should form a substantial part of the menu. Cucumber, zucchini, peas, and leafy greens can accompany algae-based tablets, spirulina foods, or vegetable flakes. Other aquarium foods are accepted, with worms and brine shrimp useful as supplements rather than replacements for vegetable offerings.

Behaviour & compatibility

Generally peaceful, silver dollars spend much of their time in the middle and upper aquarium. Larger placid catfishes can use the lower space. Very small companions may be consumed, so size remains important.

Sexual dimorphism

Males have a more extended anal fin that may carry a reddish tint.

Breeding

Group spawning requires a spacious breeding aquarium and well-conditioned fish. Favor the softer, more acidic end of the established range and a temperature near 28 °C. A slightly warmer water change may provide a stimulus.

Ready males darken around the fins and show stronger red on the chest, pursuing females and trembling beside them. Released eggs are fertilized and settle to the bottom. Removing adults afterward simplifies rearing. Hatching takes about three days. Once yolk reserves are used, offer microscopic foods before progressing to newly hatched brine shrimp and powdered diets. A pair may produce up to two thousand eggs, so nursery capacity needs advance planning.

Notes

The similar Metynnis hypsauchen has a black mark above and behind each eye, a useful distinction. The shared silver-dollar trade name alone cannot establish species identity.