Silver Dollar Care Guide
Metynnis argenteus · Easy care · 75 gallon minimum
A disc-shaped, schooling relative of the piranha that's a gentle plant-eater; needs a big tank and a group.
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How big does a silver dollar get?
A silver dollar (Metynnis argenteus) reaches about 6.0 inches as an adult. Plan tank size and tank mates around the adult size, not the small fish you buy at the store.
Tank size & setup
Give a silver dollar a minimum of 75 gallons, with water at 75–82°F and a pH of 5.5–7.5. Keep them in groups of at least 5 — they are shoaling fish and become stressed and washed-out alone. As a easy-care, herbivore species, a stable, cycled tank with the right diet keeps them healthiest.
Good tank mates
Pair a silver dollar with peaceful species that share its temperature and pH range. Compatible options include:
- Neon Tetra — 1.5", 10g min
- Guppy — 2.0", 10g min
- Molly — 4.0", 20g min
- Platy — 2.5", 10g min
- Zebra Danio — 2.0", 10g min
About the silver dollar
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 Basin in Brazil. It is one of the species known in the aquarium trade as the "silver dollar". M. argenteus is generally considered the archetypal silver dollar, although it and the very similar M. hypsauchen frequently have been confused.
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