Silver Dollar
Metynnis hypsauchen, the silver dollar, is a characin in the family Serrasalmidae, alongside piranhas and pacus. Its almost circular, strongly compressed body, clad in mirror-bright scales, earns it the coin-like name. A dark blotch sits just behind the eye, one of the few clues separating it from its trade look-alike Metynnis argenteus. The species ranges through the Amazon and Paraguay basins and the rivers of the Guiana Shield, patchily distributed from Guyana to Bolivia. It favours slow, densely planted tributaries of soft, slightly acidic water between 24 and 28 °C, grazing the submerged vegetation around it. Keep at least five together in a tank no shorter than 180 cm, since length and width matter far more than height. Feed generously on vegetable matter — courgette, cucumber, peas — or the planted decor will be eaten instead. Peaceful, it suits large calm companions. Group spawning demands a very big tank.
About the name : The name Metynnis hypsauchen (Müller & Troschel, 1844) remains valid. The species is persistently confused in the trade with the very similar Metynnis argenteus, and many profiles sold as "silver dollar" actually describe M. argenteus. Several historical synonyms exist (Myletes hypsauchen, Metynnis calichromus, Metynnis ehrhardti).
Water parameters
| Temperature | 24 – 28 °C |
|---|---|
| pH | 6 – 7 |
| General hardness (GH) | 10 °dGH |
Tank & stocking
| Minimum tank volume | 400 L |
|---|---|
| Minimum tank length | 180 cm — this active swimmer needs distance, not just litres |
| Volume budget per individual | 60 L — adds up with tank-mates |
| Minimum group size | 5 individuals (shoaling) |
“Minimum tank volume” is a reasonable floor, not an absolute limit. The per-individual budget is used by the Aqua app to estimate how heavily a tank is stocked.
Frequently asked questions
What size aquarium does Silver Dollar need?
Provide at least 400 litres for a small group to keep Silver Dollar in good conditions.
What water parameters does Silver Dollar need?
A temperature of 24–28 °C, pH 6–7.
Is Silver Dollar peaceful or aggressive?
Its temperament is peaceful.
What does Silver Dollar eat?
Its diet: herbivore.
How many Silver Dollar should be kept together?
It is a social species: keep a group of at least 5.
How big does Silver Dollar get?
Around 15 cm as an adult.
Is Silver Dollar suitable for beginners?
Care level: intermediate.
Planning a tank with Silver Dollar?
AquaTender turns these parameters into live advice: it checks whether your tank is big enough, how heavily it's stocked, and whether your fish are compatible — then tracks water tests, photos and maintenance for you.
Fish from the same biotope
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