Metynnis Argenteus

Datasheet

General Description

Metynnis argenteus, commonly known as Silver Dollars, closely resembles Metynnis hypsauchen. They are popular in the hobby and often confused with piranhas due to their predatory appearance. Silver Dollars, belonging to the Serrasalmidae family, are part of the metynnis genus, closely related to myleus and mylossoma genera. The distinguishing feature between M. argenteus and M. hypsauchen is the black blotches near the eyes of the latter.

Aquarium Setup

Silver dollars, requiring a minimum tank size of 265 liters, prefer densely planted tanks resembling their natural river tributary habitat. Opt for hardy plants or artificial alternatives due to their plant-eating behavior. Dim lighting and refuge spots in the tank help boost their confidence. Maintaining water conditions with pH levels of 6.0-7.0, hardness of 0-10 degrees dH, and a temperature range of 24-28 degrees Celsius is essential (see table).

Behaviour

Best housed in groups of at least five, Silver Dollars are peaceful community fish. They occupy the middle and top tank areas, making them compatible with larger peaceful species like certain catfish. They may prey on much smaller fish, so selecting tank mates that occupy the bottom area provides contrast within the tank setup.

Feeding and Diet

Silver Dollars thrive on a diet rich in vegetable matter such as courgette, peas, and algae wafers. They also enjoy aquarium foods like bloodworms and brine shrimp as occasional treats. Providing a varied diet and ample vegetation ensures their nutritional needs are met.

Reproduction & Dimorphism

Reproduction for Silver Dollars can be moderately difficult as they are group spawners. A large breeding tank with optimal water conditions is necessary. Males display dark coloration, especially around the fins, when ready to spawn. The presence of elongated anal fins and red tinges indicates sexual dimorphism in males. Females release eggs that hatch in about three days, yielding up to 2000 eggs per spawning pair.

Habitat and Distribution

Endemic to the Rio Tapajós drainage in Brazil, Silver Dollars inhabit river tributaries in the wild. Their natural habitat influences their tank setup requirements, making it crucial to replicate a river-like environment while considering their plant-eating tendencies.