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Encyclopedia / Tetras / Silver dollar
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Variations

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Silver dollar

Metynnis hypsauchen · Silver dollar fish, Metynnis, Plain silver dollar

Peaceful but skittish schooler; keep five or more.

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18 cmBody length, without tail ✓
24–28 °CTemperature ✓
6–7pH ✓
260 LSmallest tank ✓
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Tank mates
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Not recommended
  • Silver dollar eats animals up to about 2 cm. Ember tetra only grows to 2 cm.
Not recommended
  • Silver dollar eats animals up to about 2 cm. Chili rasbora only grows to 2 cm.
Not recommended
  • White cloud mountain minnow needs cool water and makes a lot of waste, while Silver dollar is tropical.
  • They need different temperatures (24–28 °C vs 14–22 °C). No setting suits both.
With conditions
  • Only a narrow temperature range suits both: 24–25 °C.
With conditions
  • Only a narrow temperature range suits both: exactly 24 °C.
Compatible
Compatible
Compatible
Compatible
Compatible

317 species in our list are a good match.

Facts checked against sources on 16 Oct 2026. ✓ means a source backs it; ? means no reliable source yet. See sources

Care and water

Hardness ✓0–10 dGH
Group size ✓5 or more
Temperament ✓Peaceful
Swims at ✓Middle
Care level ✓Hard
Diet Herbivore
Lifespan ?Unknown
Size in shops 3–5 cm
Growth Medium

Behavior

Peaceful but skittish schooler; keep five or more. It eats most live plants and can swallow tiny fish like neons.

Food

Spirulina flakes, vegetable pellets and blanched lettuce, spinach and peas; occasional frozen foods.

Tap a food to see what it is.

Male or female

The male's anal fin is longer and more colourful (often reddish) than the female's.

Health

Common problems. Tap one to see the signs. This is a guide, not a diagnosis.

Breeding

Egg-scatterer · Moderate

A group spawner that needs a large tank; condition the fish, then use softer, more acidic water at about 28 °C. Eggs are scattered and fertilised as they are released; the parents do not normally eat them, but eggs are usually removed to raise. Fry take infusoria, then newly hatched brine shrimp and powdered food.

Pairing

Needs a school of 6+ in a large tank; ripe females swell with eggs.

Setup

Very large tank or pond with floating plants or mops, soft slightly acidic water and warm temperatures.

What starts it

Rainy-season style water changes with soft, slightly cooler water and plenty of greens and protein.

Eggs

Up to about 2000 eggs per spawning pair; eggs hatch in about 3 days.

Raising the fry

Fry take powdered food and brine shrimp nauplii, then chopped greens; grow fast and need space.

Common mistakes
  • Tank too small
  • Keeping too few fish
  • No cover for the eggs
Full breeding guide, day-by-day plan and simulator →

Where it lives in the wild

RegionSouth America – Amazon, Orinoco & Paraguay basins and the Guianas
Rivers and lakesAmazon, Orinoco and Paraguay basins
HabitatVegetated rivers and floodplains
Native rangeAbout 2,000 km across
See it on the world map

The story of the silver dollar

A flat, round, silver relative of the piranhas and pacus from the Amazon and Paraguay basins of South America. It eats mostly plant matter and grows large enough to need a long, roomy tank. Shops sell it and the near-identical Metynnis argenteus under the same name.

Johannes Müller and Franz Troschel described this fish in 1844. It belongs to the same family as piranhas and pacus but feeds mainly on plants. Its round, silvery body gives it the name silver dollar.

First described by Johannes Müller & Franz H. Troschel in 1844. Named for 'hypsauchen' means high-necked.

  • It is a close relative of piranhas but mostly eats plants.
  • Its body is very flat and round, like a coin.
  • It is a schooling fish that feels safest in groups.

Sources

16 facts checked with sources