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Species profile

Silver Dollar

Metynnis argenteus

Common names: Silver Dollar

Recognized speciesOddballs

Adult size

Up to 15 cm

Up to 15 cm

Countries of origin

  • See all stock from Brazil

Good fit for your tank?

Good fit for

  • A keeper with room for a proper group of 10 or more

Think carefully if

  • You only want to keep one or two, because this fish needs a group of 6 or more
  • You keep smaller fish, which it may eat
  • You cannot provide about 260 litres for a fully grown fish
  • You keep shrimp you want to protect

A tall, flat, silver fish shaped like a coin, and the classic Silver Dollar. Keep a group of at least 6 in 260 litres or more.

Appearance and Identification

A tall, flat, silver fish shaped like a coin, and the classic Silver Dollar. It lives in shoals, and it eats plants, so plastic or tough plants are the only ones that last.

Check the scientific name when buying, as common names vary between sellers and countries.

Mature females are usually rounder in the belly, and males are usually slimmer and often brighter.

Tank Requirements

Suggested filter
About 1,040–1,300 litres an hour
Suggested heater
About 250–400 W for this tank
Minimum tank volume
260 litres
Minimum tank length
180 cm
Minimum group size
6
Recommended group size
10
Activity level
Active
Flow preference
Low to moderate
Planting preference
Moderately planted
Lid recommended
Yes
Jumping risk
Moderate

A long tank with open swimming water, plants around the edges and steady filtration suits this fish. A darker substrate and some floating plants usually bring out its colour.

Behaviour and Tankmates

Active and social, and most settled when kept with its own kind.

Keep a group of at least 6, and more if you can. Larger groups are calmer and show better colour and behaviour.

Not territorial, although males may spar and display.

Suits a community of similar-sized, peaceful fish that like the same water. Avoid large predators, which will treat it as food. It is likely to eat shrimp.

Check tankmates for this species

Water Parameters

Temperature
24–28 °C
pH
6–7
GH
0–10
Stability importance
Important

Keep the pH steady, because this fish is sensitive to swings. Keep the temperature steady.

Parameter caveat
Keep up regular water changes, and acclimatise new fish slowly.

Feeding

Diet types
Herbivore, Omnivore
Feeding frequency
Daily
Preferred foods
  • Spirulina or algae wafersShould make up much of the diet.
  • Blanched vegetablesCourgette, cucumber and peas work well. Remove leftovers within a day.
  • Small frozen foodsAn occasional addition for protein.

A plant-eating schooling fish. Feed vegetable-based pellets and fresh greens such as blanched courgette and peas.

Feed small amounts, and remove anything left after a few minutes.

Breeding

Breeding type
Egg Scatterer
Breeding difficulty
Difficult
Parental care
None
Baby foods
  • InfusoriaNeeded for the first days, because most fry are very small.
  • Newly hatched brine shrimpIntroduce as soon as the fry can take it.

An egg scatterer with no parental care. Adults eat eggs and fry, so use a separate tank with fine plants, moss or mesh on the bottom, and remove the adults after spawning. The fry need very small foods at first.

Habitat and Origin

Geographic origin
Brazil, South America
Natural habitat
River
Audience level
Advanced

Classification

Profile type
Recognized species
Genus
Metynnis
Family
Serrasalmidae
Species group
Fish, Oddballs

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