Silver Dollar

Metynnis argenteus

Characins

A large, peaceful schooling characin renowned for its laterally compressed, coin-like silver body. They are notorious herbivores that will devour almost any live plant in the aquarium. Highly skittish, they are known to dart rapidly when startled, requiring ample unobstructed swimming space and a tight-fitting lid.

Silver Dollar At a Glance

Adult Size15 cm
Body ShapeCompressed
Growth RateFast
TemperamentPeaceful
Water TypeFreshwater Only
Flow PreferenceModerate
Waste OutputHigh
StockingGroup of 5+

Silver Dollar Tank Requirements

Minimum Volume280 L
Minimum Length120 cm
FlowModerate
Water TypeFreshwater Only
Must-Haves in the Tank
Driftwood (Digestion/Hiding)Smooth Gravel (Sensitive Barbels)
Stocking calculator

Will Silver Dollar fit in your tank?

Care guides tell you what Silver Dollar needs, the next question is whether your tank can safely provide it. Test Silver Dollar against your tank size, maintenance needs, and the fish you already keep before you buy.

Silver Dollar
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Silver Dollar Water Parameters

Temperature2428°C
pH5.57.5
Hardness415 dGH

Silver Dollar Temperament & Compatibility

Aggression LevelPeaceful
2/10
Where They Swim
Surface
Mid-level
Bottom
Stocking Guidelines
Keep at Least5 fish
Max per TankNo limit
Can Live Alone?No — needs a group
Behavior Traits
Plant DestroyerHyperactive / Fast SwimmerShy / Slow Moving (Easily Stressed)Jumper (Lid Required)

Silver Dollar Varieties

Each variety inherits the species defaults above. Only differences are highlighted.

Standard

The standard silver dollar seen in the trade. Must be kept in groups of 5 or more to prevent panic and stress. Best kept in a hardscape-only aquarium (driftwood and smooth rocks) as they will eat live plants down to the stems.

Same care requirements as the base species

Also known as: Common Silver Dollar

Silver Dollar Care Guide Summary

The Silver Dollar, scientifically known as Metynnis argenteus, belongs to the Characins family group. Adults reach a maximum size of approximately 15 cm and have a compressed body shape with a fast growth rate. Classified as peaceful, this species primarily occupies the mid-level and surface zones of the aquarium and produces a high level of biological waste.

To thrive, the Silver Dollar requires a freshwater only aquarium with a minimum volume of 280 litres and a tank length of at least 120 cm. Water temperature should be maintained between 24°C and 28°C, with a pH range of 5.57.5 and a general hardness of 415 dGH. A moderate water flow is preferred.

The Silver Dollar is a rewarding species to keep, provided its core environmental needs are met. The Silver Dollar is typically available in one standard form.

Silver Dollar Habitat Setup

When setting up an aquarium for the Silver Dollar, a moderate water flow best suits their natural preferences. Because this species occupies the mid-level and surface zones, the aquarium layout should prioritise adequate surface area with floating cover to make them feel secure near the waterline and open swimming space in the centre of the tank for free movement. Useful additions include smooth gravel or rounded substrate to protect their sensitive barbels and driftwood, which can serve as both a hiding place and a dietary supplement. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper and live planted layouts may be difficult to maintain, as this species tends to uproot or consume vegetation.

Silver Dollar Compatibility Notes

Classified as peaceful, the Silver Dollar is a social species that requires the company of its own kind to thrive. Selecting tankmates that favour different water layers from the mid-level and surface zones can help reduce competition and territorial overlap.

Silver Dollar Recommended Tank Sizes

Standard aquarium sizes that meet the minimum volume and length requirements for Silver Dollar.

Show 1 more tank size

Frequently Asked Questions About Silver Dollar

How big does Silver Dollar get?

Silver Dollar (Metynnis argenteus) typically reaches a maximum adult size of approximately 15 cm. They have a compressed body shape and a fast growth rate.

What tank size does Silver Dollar need?

A minimum aquarium volume of 280 litres and a tank length of at least 120 cm are recommended for Silver Dollar. This ensures enough swimming space and helps maintain stable water conditions.

What water parameters does Silver Dollar need?

Silver Dollar thrives in freshwater only conditions with a temperature range of 24–28°C, a pH between 5.5 and 7.5, and a general hardness of 4–15 dGH. A moderate water flow is preferred.

Is Silver Dollar peaceful or aggressive?

Silver Dollar is classified as peaceful with an aggression score of 2 out of 10. They are generally well-suited to peaceful community tanks.

Can Silver Dollar live alone?

No, Silver Dollar should be kept in groups of at least 5 to reduce stress and encourage natural behaviour.

Does Silver Dollar have any special tank requirements?

Yes. Silver Dollar benefits from driftwood (digestion/hiding) and smooth gravel (sensitive barbels) in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.

Does Silver Dollar need a lid on the tank?

Yes. Silver Dollar is a known jumper, and a tight-fitting lid or cover is essential to prevent escape. Even a small gap can be enough for a determined fish to leap out.


Fish Similar to Silver Dollar

Plain Silver Dollar

Metynnis hypsauchen

Characins
15 cm Peaceful

A large, peaceful, schooling characin closely related to pacus and piranhas. Unlike their carnivorous cousins, Silver Dollars are primarily herbivorous and are notorious plant destroyers. They are highly active and easily startled, requiring large tanks with plenty of open swimming space, dim lighting or cover, and a tight-fitting lid to prevent jumping.

Pink Tailed Chalceus

Chalceus macrolepidotus

Characins
25 cm Semi-Aggressive

A large, incredibly active, and fast-swimming characin from South America known for its shimmering silver body and striking pink tail. They are primarily surface dwellers and are notorious jumpers, so a tight-fitting lid is absolutely mandatory. While generally peaceful with larger tankmates, they are predatory and will consume small fish. They must be kept either singly or in a shoal of 6+; small groups often result in severe squabbling.

Silver Hatchetfish

Gasteropelecus sternicla

Characins
5 cm Peaceful

A uniquely shaped characin with a deep, keeled belly adapted for surface dwelling. Known as 'flying fish', they possess powerful pectoral fins used to leap from the water to catch insects or escape predators. A tight-fitting lid with absolutely no gaps is mandatory. They are peaceful schooling fish that require open surface swimming space and floating plants to feel secure.

Head and Tail Light Tetra

Hemigrammus ocellifer

Characins
4.5 cm Peaceful

A peaceful, schooling characin named for the reflective copper/gold spots on its head and the base of its tail. These 'lights' evolved to help the school stay together in the dark, tannin-stained waters of the Amazon basin. They are hardy, active, and make excellent community fish for planted aquariums.

Panda Tetra

Aphyocharax paraguayensis

Characins
4 cm Mostly Peaceful

A small, highly active, and strikingly marked characin native to the Paraguay River basin. Known as the Panda or Dawn Tetra, it features a metallic silver body with distinctive black and white markings on its tail and anal fins. While beautiful and hardy, they are notorious fin-nippers. They must be kept in larger schools to disperse aggression and should never be housed with slow-moving or long-finned fish (like Bettas or Angelfish).

Glass Bloodfin Tetra

Prionobrama filigera

Characins
6 cm Peaceful

A highly active, schooling characin characterized by its translucent body and striking blood-red anal fin. They are peaceful but exceptionally fast-moving, requiring plenty of open horizontal swimming space in the upper levels of the aquarium. They are known to be skilled jumpers, making a tight-fitting lid mandatory.