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Silver Dollar

By The Aquarium Calculators Editorial Team ·

Metynnis argenteus

Complete Silver Dollar care guide covering herbivore diet requirements, peaceful temperament, minimum 75 Gallons tank setup, and compatible freshwater tankmates. Difficulty: Easy.

Silver Dollar

Quick Answer

Silver Dollar (Metynnis argenteus) is a deep-bodied characin from South America. It requires a minimum 75 Gallons aquarium with a pH of 5.5 - 7.5 and temperature range of 24-28°C. This herbivore occupies the middle zone and makes an excellent addition to community setups.

Intro

Silver Dollar (Metynnis argenteus) is a deep-bodied characin from South America. Its thin, flat shape and silver color make it look like a silver coin.

Setup

A 75-gallon or larger tank (long) with open swimming space. They eat live plants, so use plastic or very hardy plants (Java fern attached to wood). Dim lighting and floating plants.

Feeding

Herbivorous; eats vegetable flakes, spirulina pellets, blanched vegetables (zucchini, spinach), and occasional protein foods. Avoid overfeeding protein.

Compatibility

Peaceful schooling fish. Keep in groups of 6+. Good with similarly sized peaceful fish: large tetras, rainbowfish, severums, Geophagus.

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Tank Position
Middle
Water Temp
24-28°C
Adult Size
See profile
Water pH
5.5 - 7.5

Species Characteristics

Adult Size
Lifespan
Growth Rate
moderate
Tank Compatibility
Community compatible
Indoor Aquarium
Yes

Water Parameters

Water Temperature
Humidity
Water pH

Tank Lighting

Tank Lighting
Standard lighting
Light Hours
N/A
Intensity
moderate

Feeding & Diet

Diet Type
Diet: Herbivore
Feeding Schedule
N/A
Live Food Options
N/A

Continue Learning

Recommended Tools

Fish Compatibility Calculator fish compatibility

Health & Disease

Ich (White Spot Disease) common disease • all fish

Related Guides

Understanding pH in Aquariums water parameters • ph

Similar Species

African Red Eyed Tetra Care Guide: Schooling & Tank Size semanticSimilarity Apistogramma Care Guide: Temperament & Diet semanticSimilarity Banded Corydoras Care Guide: Substrate & Diet semanticSimilarity

Frequently Asked Questions

How many Silver Dollars should be kept together?
Maintain a minimum school of 6 to 8 individuals in a tank of at least 75 gallons (284 liters) with a footprint of 48x18 inches (120x45 cm). Silver dollars (Metynnis argenteus) are large, active relatives of the pacu that require wide, open swimming lanes. Groups under 5 cause chronic stress and hiding. A school of 10+ displays natural schooling behavior. Provide open swimming areas and robust plants (Java fern, Anubias) as they will consume soft-leaved plants. Tank length must exceed 48 inches (120 cm).
What are the exact water parameters for Silver Dollars?
Target pH 5.5 - 7.5, General Hardness 4 - 12 dGH, Carbonate Hardness 3 - 10 dKH, Total Dissolved Solids 100 - 300 ppm, Electrical Conductivity 200 - 600 μS/cm, and temperature 75°F - 82°F (24°C - 28°C). They are hardy but require excellent filtration (10x turnover) due to waste production. Maintain nitrates below 20 ppm with weekly 30% water changes. Use a canister filter. Provide open swimming lanes and smooth gravel. Hardness below 4 dGH causes clamped fins.
What is the dietary and medication protocol for Silver Dollars?
They are dedicated herbivores requiring 80% plant matter, 15% protein, 5% fat. Feed premium spirulina flakes, vegetable wafers, lettuce, blanched peas, zucchini, and spinach daily. Supplement with frozen bloodworms or brine shrimp once weekly. They will decimate live aquarium plants. Medication alert: Tolerate copper (0.2 mg/L) and formalin. Praziquantel is safe. Salt baths up to 5 ppt treat external parasites. Quarantine with methylene blue for 7 days. They are susceptible to ich; treat with malachite green at half-dose.
How to breed Silver Dollars in captivity?
Breeding is rare but possible in large tanks (100+ gallons). Condition a group of 8-10 with spirulina flakes and blanched peas for 4 weeks. Simulate rainy season: Lower pH to 6.0, raise temperature to 82°F (28°C), perform 40% water change with cool (70°F/21°C) soft water. Provide fine-leaf plants as egg-scattering sites. Female releases 2,000-5,000 eggs. Remove parents after spawning. Eggs hatch in 24-36 hours at 80°F (27°C). Fry require green water for 5 days, then baby brine shrimp, then crushed spirulina flakes. Not recommended for beginners.

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