Silver Dollar – 10cm (Metynnis argenteus)

The Silver Dollar  is a top water schooling fish that are large, peaceful and active. They are hardy but recommended for the intermediate aquarist due to their large size.  Adult size is up to 15 cm in length.

Silver Dollar Fish (Metynnis argenteus) get their name from the way they look: large silvery fish from South American rivers.  They belong to the Characidae family, the same family as Piranha and Pacu. However in contrast to their more aggressive relatives, they are peaceful herbivorous fish, perfect for large size community aquariums.  Their scientific name describes the fish perfectly. Metynnis, meaning ‘with plowshare’ which refers to the laterally flattened body, and, argenteus, meaning ‘covered with silver’.

Behavior

If you are looking for top water schooling fish, they are one of the best choices.  Silver Dollars are a lively schooling fish and best kept in groups of three or more.  They can be quite skittish and reclusive if kept alone. Rocks, plants (try java fern and hornwort as they are not very tasty), and driftwood help mirror its natural habitat and will help to reduce stress on the fish, though plastic plants may be necessary due to their herbivorous nature. Interestingly, they are are pelagic fish, which means they will spend most of their time swimming close to the water surface. They get startled easily and will jump out of the tank.

Silver Dollar Fish are large peaceful and active fish but during eating time they can be aggressive and chase each other around the tank.  Silver Dollars are at their best when kept together. They are schooling fish, so they feel safer and more protected in a group.

Tank Conditions

They can get startled and jump, so a covered tank is a must.  They will mainly swim in the middle and top part of the water column and therefore need open areas for swimming.  These fish are quite hardy and have some tolerance toward different water conditions. They require clean and well oxygenated waters with a good filtration system and moderate flow. A couple of power heads can be used to help out with water movement and oxygenation.

They are jumpy fish, preferring dim lighting and a dark background. We suggest using dark colored gravel as a substrate. You need a lot of open space but also some hiding places around the back and sides of the tank (you can build these with large rocks and driftwood).

As they are herbivores, you should only keep plants that are not very tasty; try java fern and hornwort. The alternative is to use artificial plants.

Compatibility

They are great community fish that swim in the top part of the aquarium. If you want to add some contrast, you can look for other large peaceful fish such as catfish that spend most of their time near the tank bed. Plecos and Doradids could be a good fish to start with. Further ideal tank mates are peaceful South and Central American Cichlids such as freshwater Angelfish, Firemouth and Green Terror Cichlids. Giant Danios, Pacus and Anostomus are also good tank companions.  Do not keep your Silver Dollars with smaller fish such as Gouramis, Bettas and Tetras as they might get eaten.  Shrimps and snails can be a good addition; however they too might get eaten.

Feeding

Silver Dollars are actually omnivorous fish; however, they prefer an herbivorous diet. In nature they usually feed on the surrounding vegetation including terrestrial plants.  You can feed them a variety of plants such as lettuce, cress, chickweed, cucumber, peas and spring greens. You can also feed them seaweed such as spirulina along with large vegetable flakes.

Care

They do best in soft, slightly acidic water with high filtration.  The water should be replaced on a regular basis and at least 25-50% of the water should be replaced every other week.

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