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.
At a Glance
Tank Requirements
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Water Parameters
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Temperament & Compatibility
Available 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
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🟢Ideal Tank MatesSilver 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 5.5–7.5 and a general hardness of 4–15 dGH. A moderate water flow is preferred. An aquarium test kit can help you monitor these values.
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. Browse smooth aquarium gravel options to find the best fit.
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.
Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Silver Dollar.
75 Gallon Standard
90 Gallon Standard
125 Gallon Standard
150 Gallon High
180 Gallon Standard
350 Liter (120cm Deep)
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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.
Similar Species
Penguin Tetra
Thayeria boehlkei
An active schooling characin instantly recognizable by its bold black horizontal stripe that extends down into the lower half of the tail fin, and its unique, oblique (head-up) swimming posture. They are hardy and do well in community tanks, but must be kept in groups to prevent stress and fin-nipping behavior towards tank mates.
Tinfoil Barb
Barbonymus schwanenfeldii
A large, active, and schooling riverine species that quickly outgrows standard aquariums. Known for their metallic silver scales and red fins. They are notoriously skittish, robust eaters, and will consume almost any live plant or small fish that fits in their mouths. A massive tank with strong filtration is strictly required.
Rummy-Nose Tetra
Hemigrammus rhodostomus
Renowned as the tightest schooling fish in the freshwater hobby. They feature a bright red nose, a silver body, and a black-and-white checkered tail. They are excellent 'indicator fish'; their red noses will fade to pale pink if water quality drops or the fish are stressed. While there are three very similar species (H. rhodostomus, H. bleheri, P. georgiae) often sold under the same name, their care requirements are identical.
Silver Arowana
Osteoglossum bicirrhosum
A massive, prehistoric-looking surface predator native to the Amazon Basin. Known for their metallic silver scales and incredible jumping ability (used in the wild to catch insects from low-hanging branches). They grow exceptionally fast and require gigantic aquariums. They will consume any tank mate small enough to fit into their large, trapdoor-like mouths.
Serpae Tetra
Hyphessobrycon eques
A striking, deep-red schooling fish known for its highly active nature. While hardy and beautiful, Serpae Tetras are notorious fin-nippers. This behavior is usually localized within their own pecking order if kept in large enough schools (8+), but they should never be housed with slow-moving or long-finned tank mates like Bettas, Angelfish, or Gouramis.
Marbled Hatchetfish
Carnegiella strigata
A uniquely shaped, peaceful surface-dwelling characin famous for its deep, keeled belly and incredible jumping ability. In the wild, they can leap from the water and 'fly' short distances using their powerful pectoral fins to catch insects or escape predators. A tight-fitting lid with absolutely no gaps is mandatory. They require floating plants to feel secure and must be kept in schools.