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.
Plain Silver Dollar At a Glance
Plain Silver Dollar Tank Requirements
Will Plain Silver Dollar fit in your tank?
Care guides tell you what Plain Silver Dollar needs, the next question is whether your tank can safely provide it. Test Plain Silver Dollar against your tank size, maintenance needs, and the fish you already keep before you buy.
Useful setup supplies
We may earn from qualifying purchases
Plain Silver Dollar Water Parameters
Water care products
We may earn from qualifying purchases
Plain Silver Dollar Temperament & Compatibility
Plain Silver Dollar Varieties
Each variety inherits the species defaults above. Only differences are highlighted.
Standard
The typical adult form. Due to their skittish nature, they must be kept in schools of 5 or more to feel secure. They will rapidly consume almost any live aquarium plants, so artificial plants or very hardy species (like Anubias) are recommended.
Same care requirements as the base species
Also known as: Adult, Classic Silver Dollar
Juvenile (Grow-out)
Juveniles are commonly sold at the size of a large coin (3-5cm). They grow rapidly and will quickly outgrow small aquariums.
Differs in 4 traits from base species
Also known as: Baby Silver Dollar, Coin Size
Plain Silver Dollar Care Guide Summary
The Plain Silver Dollar, scientifically known as Metynnis hypsauchen, 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 Plain 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 6–7.5 and a general hardness of 4–15 dGH. A moderate water flow is preferred.
The Plain Silver Dollar is a rewarding species to keep, provided its core environmental needs are met. This species is available in 2 varieties: Standard and Juvenile (Grow-out). Each may differ slightly in size, temperament, or care needs, so it is worth checking the specific requirements of the variety you plan to keep.
Plain Silver Dollar Habitat Setup
When setting up an aquarium for the Plain 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.
Plain Silver Dollar Compatibility Notes
Classified as peaceful, the Plain 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.
Plain Silver Dollar Recommended Tank Sizes
Standard aquarium sizes that meet the minimum volume and length requirements for Plain Silver Dollar.
75 Gallon Standard
90 Gallon Standard
125 Gallon Standard
150 Gallon High
180 Gallon Standard
350 Liter (120cm Deep)
Show 1 more tank size
Feeding products
We may earn from qualifying purchases
.webp?2026-04-25T14%3A35%3A38.022Z)
Frequently Asked Questions About Plain Silver Dollar
How big does Plain Silver Dollar get?
Plain Silver Dollar (Metynnis hypsauchen) 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 Plain Silver Dollar need?
A minimum aquarium volume of 280 litres and a tank length of at least 120 cm are recommended for Plain Silver Dollar. This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Plain Silver Dollar need?
Plain Silver Dollar thrives in freshwater only conditions with a temperature range of 24–28°C, a pH between 6 and 7.5, and a general hardness of 4–15 dGH. A moderate water flow is preferred.
Is Plain Silver Dollar peaceful or aggressive?
Plain 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 Plain Silver Dollar live alone?
No, Plain Silver Dollar should be kept in groups of at least 5 to reduce stress and encourage natural behaviour.
Does Plain Silver Dollar have any special tank requirements?
Yes. Plain Silver Dollar benefits from smooth gravel (sensitive barbels) and driftwood (digestion/hiding) in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Does Plain Silver Dollar need a lid on the tank?
Yes. Plain 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.
Top Tank Mates for Plain Silver Dollar
These fish are strong compatibility matches for Plain Silver Dollar based on water preferences, temperament, adult size, and tank behavior.
Apistogramma Marmor (Marbled Apisto)
Apistogramma erythrura
Ideal Tank MatesAlligator Pleco
Pterygoplichthys scrophus
Ideal Tank MatesGolden Bristlenose Pleco
Ancistrus sp. L144
Ideal Tank MatesAssassin Snail
Anentome helena
Ideal Tank MatesBristlenose Pleco
Ancistrus cf. cirrhosus
Ideal Tank MatesApistogramma Resticulosa Mamor
Apistogramma cf. resticulosa Mamor
Ideal Tank MatesPlants That Suit Plain Silver Dollar
These plants pair well with Plain Silver Dollar based on shared water preferences, layout fit, and how likely they are to hold up in the same aquarium.
African Onion Plant
Crinum calamistratum
Afzel's Anubias
Anubias afzelii
Anubias Barteri
Anubias barteri
Balansae
Cryptocoryne crispatula
Belinda's Buce
Bucephalandra belindae
Bonsai Rotala
Rotala indica
Fish Similar to Plain Silver Dollar
Silver Dollar
Metynnis argenteus
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.
Black Pacu
Colossoma macropomum
The Black Pacu (Tambaqui) is a massive, incredibly fast-growing Amazonian fish. Closely related to Piranhas, they possess crushing, human-like teeth evolved for cracking nuts and seeds. Due to their enormous adult size (often exceeding 3 feet and 60 lbs) and extreme bioload, they are completely unsuitable for standard home aquariums and require colossal custom tanks or heated indoor ponds.
Red-Bellied Piranha
Pygocentrus nattereri
An infamous South American predator known for its razor-sharp teeth and schooling behavior. Despite their fearsome reputation, they are naturally skittish and easily spooked in aquariums, requiring a large shoal (4-6+) and dim lighting (often achieved via floating plants) to feel secure. They are incredibly messy eaters that produce extreme bioloads, necessitating massive filtration systems and frequent water changes.
Silver Datnoid (Silver Tigerfish)
Datnioides polota
A striking predatory fish known for its deep body and tiger-like stripes. Unlike other Datnoids, the Silver Datnoid is euryhaline and naturally inhabits estuaries; while it can survive in freshwater, it thrives in light brackish conditions. They are ambush predators with highly protrusible jaws capable of swallowing surprisingly large prey.
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.
Andinoacara sp. Gold Saum
Andinoacara sp. "Gold Saum"
Commonly sold in the aquarium trade as the 'Green Terror', the Gold Saum (technically Andinoacara rivulatus) is a stunning but highly aggressive Neotropical cichlid. Males develop magnificent iridescent scales, orange/gold-edged fins, and a pronounced nuchal hump. Due to their territorial nature and large adult size, they are best kept as solitary centerpiece fish or with highly robust, similarly-sized tank mates. They are avid diggers and will uproot or destroy most live plants.