Silver Dollar fish (Metynnis argenteus) - 4 cm

The Silver Dollar fish (Metynnis argenteus) is a highly popular, shimmering, coin-shaped freshwater fish native to the river basins of South America. Despite being close relatives of the aggressive piranha, Silver Dollars are remarkably peaceful, hardy, and social schooling fish that make excellent additions to large community aquariums.

Tank Requirements & SetupTank

Size: Minimum 75 gallons for a school of 5 to 6 fish. They need a long tank (at least 4 to 6 feet) because they are incredibly fast, active swimmers.

Aquarium Plants: Use plastic or silk plants. Silver Dollars are strict herbivores and will rapidly shred and eat almost any live plants in the tank.

Security: A tight-fitting lid is mandatory. These fish are easily startled and are notorious high-jumpers.

Diet and Feeding

Silver Dollars are primary herbivores. Their diet should be rich in plant matter to prevent malnutrition:

Commercial food: Spirulina flakes, vegetable pellets, and algae wafers.

Fresh greens: Blanched zucchini, cucumber, spinach, and lettuce.

Proteins: Occasional treats of brine shrimp or bloodworms.

Ideal Tank Mates

Because they grow up to 6 inches in diameter and are very peaceful, they should not be housed with tiny fish like neon tetras, which might accidentally be eaten.

Great tank mates include:

Medium-to-large Central/South American Cichlids (like Oscar fish, Severums, and Blue Dempseys)

Large catfish species and Plecos

Clown Loaches and Bala Sharks