The Silver Dollar (Metynnis argenteus) is a freshwater tropical fish. It is a serrasalmid from the Characidae family – the serrated salmon family – such as the pacu and piranha.
The Silver Dollar has a round, flat body that is laterally compressed (thin). It is silver all over, with a hint of red in its fins, especially its tail fin, and around its throat. During the breeding season, the male has two large black spots behind its pectoral fins, the red colour deepens, and a black margin (border) appears on his fins.
It grows to 13-16 centimetres (5-6 inches) in length.
It is endemic to the Tapajos River Basin in Brazil in South America. It prefers rivers with weeds, and likes to swim in the mid to upper level of the water.
It is a shoaler, which means that the group of fish stay together in schools, swimming in the same direction in a coordinated manner. It is timid, and will hide if threatened.
It is herbivorous, eating aquatic plants. It may also eat worms and insects.
The female scatters her eggs among thin plant leaves or on the bottom of the river. She spawns about 2,000 eggs. The eggs hatch after three days into small fish, called fry. The parents do not eat their young. The fry can swim and feed by themselves after 7 days.
The Silver Dollar lives, on average, for more than 10 years.
[Location of photographs: Tbilisi Zoo, Georgia]
Photographer: Martina Nicolls
Martina Nicolls: SIMILAR BUT DIFFERENT IN THE ANIMAL KINGDOM