Silver Dollar

Care at a glance

Overview

This is a schooling fish that needs a group of at least five, and because of its size and activity it really needs a big tank, around 265 liters or more. It swims in the middle and upper water and is mostly peaceful, though it can be nervous and skittish in small groups. The diet is almost entirely plant-based: spirulina, vegetable flakes, and fresh greens like spinach or lettuce. Keep the water soft to neutral and warm.

In the wild

Silver dollars live in the Amazon basin across Guyana, Brazil, Peru, and Bolivia, in slow, warm waters with plenty of plants and soft bottoms. The water is warm and slightly acidic with lots of organic matter. In the tank, give them open swimming room, soft to neutral water, and a temperature in the mid to high 20s C. Note that they will eat live plants, so plan around that.

Good to know

Metynnis hypsauchen belongs to the family Characidae and is a close relative of pacus and piranhas. It has a round, flat, coin-shaped body and reaches about 14 cm. It is an egg scatterer and breeding it at home is difficult. The very similar Metynnis argenteus shares the same common name.

Did you know

Their flat, silvery, disc-shaped bodies act like mirrors that scatter light, which breaks up their outline in open water and makes them harder for predators to pick out from a moving school.

Related species

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  Silver Dollar

  Metynnis argenteus

  5.9 in (15 cm)70 gal (265 L)75–82°F (24–28°C)

• 

  Buenos Aires tetra

  Hyphessobrycon anisitsi

  3 in (7.5 cm)25 gal (95 L)66–81°F (19–27°C)

• 

  Blind cave tetra

  Astyanax mexicanus

  4.7 in (12 cm)25 gal (95 L)70–77°F (21–25°C)

• 

  Bucktooth tetra

  Exodon paradoxus

  4.7 in (12 cm)45 gal (170 L)73–82°F (23–28°C)

• 

  Red eye tetra

  Moenkhausia sanctaefilomenae

  2.8 in (7 cm)28 gal (105 L)72–79°F (22–26°C)

• 

  Black widow tetra

  Gymnocorymbus ternetzi

  2.4 in (6 cm)20 gal (75 L)68–79°F (20–26°C)