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Metynnis argenteus

Silver dollar (Metynnis argenteus) - Tetra Fish for Sale UK

Moderate Care
Peaceful
£94.99Sold Out
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A peaceful, fast-swimming schooling fish with a striking silver disc-shaped body that makes a bold display in large aquariums. Moderate care, peaceful. 24-28C, pH 6-7.5.

Care at a Glance

Scientific Name
Metynnis argenteus
Max Adult Size
up to 22 cm
Lifespan
10 years
Care Level
Moderate
Temperament
Peaceful
Temperature
24–28°C
pH Range
6–7.5
Hardness
2–15 dGH
Minimum Tank
500L
Diet
Omnivore with strong plant matter preference

Adult size is the maximum length this species reaches at full maturity (scientific sources). The livestock you receive will be younger and smaller — pick a size above for the actual shipping size. Product-photo provenance and any image-specific limitations are stated on the listing.

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Water Parameters

Maintain these water conditions for optimal health and vibrant colors

Temperature
24–28°C
24°CIdeal28°C
pH Level
6–7.5
6Ideal7.5
Water Hardness
2–15 dGH
2 dGHIdeal15 dGH

Overview of Silver dollar

The silver dollar, scientifically known as Metynnis argenteus, a classic, peaceful schooling fish with a bright silver body and fast, graceful swimming behavior, ideal for large south american community aquariums.. Metynnis argenteus is a species of freshwater ray-finned fishes belonging to the family Serrasalmidae, which includes the pacus, piranhas and related fishes. This fish is endemic to the Tapajós River

Native to Tapajós River Basin, Brazil; Amazon basin, South America, this moderate-care species belongs to the Serrasalmidae family and has earned a loyal following among UK aquarists for its unique characteristics and manageable requirements.

Quick Facts

  • Scientific Name: Metynnis argenteus
  • Family: Serrasalmidae
  • Adult Size: 20 cm
  • Minimum Tank: 400 litres
  • Care Level: Moderate
  • Temperament: Peaceful

Appearance and Distinguishing Features

True to its name, the silver dollar fish displays a round, disc-shaped body with brilliant silver scales that catch and reflect light. Adults can reach an impressive 20 cm, making them a substantial presence in larger aquariums.

At Tropical Fish Co, we select only the healthiest specimens with vibrant coloration and active behavior, ensuring you receive premium quality fish for your aquarium.

Natural Habitat and Origin

In the wild, Metynnis argenteus inhabits tapajós river basin, brazil; amazon basin, south america. Understanding their natural environment helps us replicate optimal conditions in the home aquarium.

These waters are typically soft, slightly acidic, and rich in tannins from decomposing leaf litter. Dense vegetation provides shelter and feeding opportunities, while seasonal flooding creates dynamic habitat conditions.

Aquarium Setup and Requirements

A minimum tank size of 400 litres is essential for housing Silver dollar. Larger aquariums provide more stable water chemistry and greater swimming space, both critical for long-term health.

Provide appropriate hiding places, suitable substrate, and decorations that match their natural habitat preferences. Good filtration and stable water parameters are essential for all freshwater species.

Invest in quality filtration capable of turning over the tank volume 4-6 times per hour, and perform regular 25-30% water changes weekly to maintain pristine conditions.

Expert Tip

Always keep Silver dollar in groups of 6+ individuals. Smaller groups cause stress, faded colors, and abnormal behavior. Larger schools create spectacular displays!

Water Parameters and Chemistry

Maintaining correct water parameters is crucial for the health of Silver dollar:

  • Temperature: 24-28C
  • pH Range: 6.0-7.5
  • Hardness: See species-specific requirements
  • Ammonia/Nitrite: 0 ppm (zero tolerance)
  • Nitrate: Below 20 ppm ideally

This species prefers soft, acidic water. Use RO water remineralized to appropriate GH/KH, add Indian almond leaves or alder cones for tannins, and avoid calcareous decorations that raise pH.

Invest in quality test kits and check parameters weekly. Stability is more important than hitting exact numbers - avoid sudden changes that stress fish.

Feeding and Nutrition

As a omnivore with strong herbivorous tendencies, Silver dollar requires a carefully balanced diet to maintain optimal health and coloration.

Primarily plant-based with some omnivorous tendencies; offer a varied diet of high-quality spirulina-based flakes or pellets, blanched vegetables such as spinach, zucchini, and peas, plus occasional...

Vary the diet between quality flakes/pellets, frozen foods (bloodworms, daphnia, brine shrimp), and occasional fresh vegetables. Nutritional variety promotes vibrant colors, strong immunity, and natural behavior.

Remove uneaten food after 3-5 minutes to prevent water quality degradation. A single weekly fasting day can benefit digestion and overall health.

Behaviour and Temperament

The Silver dollar is classified as peaceful, though individual personality can vary with age, tank size, and stocking density.

This peaceful species thrives in community setups with similarly sized, non-aggressive tankmates. Calm demeanor and gentle nature make it ideal for planted aquariums.

Best kept in a spacious, well-filtered aquarium with open swimming room and secure cover; they are schooling fish that become stressed and skittish when kept singly or in small numbers. Provide...

Compatible Tank Mates

Choose tankmates carefully to ensure a harmonious community aquarium:

Compatible species include:

  • Other silver dollars
  • Peaceful medium to large South American community fish
  • Peaceful plecos
  • Geophagus and other peaceful cichlids of similar size

Avoid housing with:

  • Small fish that can be swallowed
  • Fin-nipping species
  • Aggressive cichlids
  • Large predatory fish
  • Very delicate slow-moving fish

Always research specific compatibility and introduce new fish gradually, monitoring behavior closely during the first few weeks.

Breeding and Reproduction

Breeding is uncommon in home aquariums; pairs or groups may spawn in soft, warm water with dense planting or fine-leaved cover, and adults may eat eggs and fry.

Why Buy Silver dollar from Tropical Fish Co UK

When you choose Tropical Fish Co for your silver dollar purchase, you benefit from:

  • Premium Quality: Every fish is quarantined, health-checked, and feeding well before dispatch
  • Expert Selection: We hand-pick active, vibrant specimens with excellent coloration
  • Safe Delivery: Specialist courier service with heat packs and double-bagged packaging
  • Live Arrival Guarantee: We stand behind every shipment with our comprehensive guarantee
  • Ongoing Support: Expert care advice available whenever you need it

With decades of combined experience in the UK aquarium trade, we understand what makes healthy, thriving fish. Our Silver dollar specimens are among the finest silver dollar available online today.

Order with confidence knowing you're purchasing from a trusted UK specialist. We're passionate about connecting aquarists with exceptional fish for sale UK wide.

Customer Reviews

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What customers say about ordering from us

  • 4 out of 5Verified buyer

    I have a small group of long finned mountain minnows. So was delighted to be able to order ten of this variety to increase the genetics in my tank . The ones I recieved are healthy but it’s to early to give a verdict on wether they are of a long finned type since they are small currently.

    Gordon Walker · 23 Sept 2026

  • 5 out of 5Verified buyer

    100% success travel and "installation". Pleased with quality of purchase. The Siamese fighter a bit "shy" so have not yet seen him at his best yet but looking good. Happy customer. GG

    George E Garratt · 21 Sept 2026

Reviews of our shop, collected by Judge.me, an independent third-party review collector. Newest first.