施氏银板鱼 · Silver Dollar

Overview

Metynnis hypsauchen is a deep-bodied silver fish whose dark mark above and behind each eye helps distinguish it from similar silver dollars. Although related to piranhas, its practical care challenges include group space, plant damage, and nervous behavior.

Distribution & habitat

It has a discontinuous range in parts of Guyana, Brazil, Peru, and Bolivia. Records include the Amazon, Paraguay, and northern rivers of the Guiana Shield. Densely vegetated tributaries provide habitat.

Aquarium setup

An adult group needs a footprint around 180 × 38 cm or larger. Floor dimensions matter more than additional height. Keep at least five and provide subdued light with sheltered areas to encourage confidence.

Living vegetation is readily eaten, including plants that initially appear durable. Soft, suitable artificial plants can provide cover when repeated replacement of real plants becomes impractical.

Diet & feeding

Offer abundant plant material, including cucumber, zucchini, peas, and greens, alongside algae tablets, spirulina foods, or vegetable flakes. Most other aquarium foods are accepted too, with worms and brine shrimp suitable as supplements.

Behaviour & compatibility

Silver dollars are generally peaceful and use the middle and upper parts of the aquarium. Larger placid catfishes are possible companions for the lower space, while very small fishes may still be eaten.

Sexual dimorphism

The male's anal fin is longer and more brightly colored.

Breeding

Group spawning in silver dollars calls for conditioned adults and a spacious breeding setup. Aim toward the softer, more acidic part of the established range, at about 28 °C. A change using slightly warmer water may stimulate activity.

Males darken, particularly around the fins, and intensify red on the chest before pursuing and trembling beside females. Eggs are released, fertilized, and settle to the bottom. Remove adults after spawning to simplify nursery care. Hatching takes roughly three days. Offer microscopic live food after yolk absorption, progressing to newly hatched brine shrimp and powdered food as growth permits. A pair may produce around two thousand eggs, requiring adequate rearing space.

Notes

It closely resembles Metynnis argenteus in appearance and care. The dark mark behind and above each eye is a useful distinction. A striped form also occurs, but that pattern alone does not establish a separate species.