The silver dollar fish, scientifically known as metynnis hypsauchen, is so called because of its bright silver color, and its round, flat shape. It is about 6 inches in size. There is also another variety of this fish called the red hook silver dollar, that has a red color on its anal fin, which is generally the male gender of this breed. With its cool temperament and basic feeding requirements, this fish is a good choice for beginners who are interested in having fish as pets. Care

• These fish do not fare well on their own. They require a school of minimum 6 other fish, else they scare easily.
• Invest in at least a 75-gallon fish tank when maintaining a school of this fish breed, for easy movement and their skittish behavior.
• Because these fish scare easily, be careful and sensitive in your approach towards them. Even rapid movements will cause them to scurry around the tank, which may result in their injury.
• Avoid fancy decorations in their tanks and provide them with a dark substrate.
• They do not like bright light, and would prefer dim lighting around them. Thus, giving them a place to hide inside the tank, away from direct light, would be a good idea.
• Maintain the water temperature in the tank at 75 to 82 °F (24 to 28 °C). Even while changing the water in the tank, try to maintain the same temperature, as fluctuations in water temperature may not go down too well with them. They survive well in soft and moderately acidic water. It is important to change the filter in the tank regularly, as a rise in nitrate levels in stale water can harm them.
• Due to their calm nature, silver dollars are compatible with several other fish breeds, and can be easily kept with a different variety of fish.

Food Unknown to many, the silver dollar fish belongs to the piranha family. Even so, it is a herbivorous fish as compared to its carnivorous counterparts. Though the diet is different, the eating pattern of both the fish breeds is similar―aggressive. As such, avoid placing live plants as a decoration in the tank, as they won't survive to see the light of day. A plastic substitute is good. As part of their diet, these fish will eat vegetables in a flaked form, namely, cooked romaine lettuce, spirulina, spinach, and watercress. Algae wafers are also a good choice as part of their diet. Other options are to mix vegetables such as squash, peas, and zucchini in a flake form. As an occasional treat, they can be given certain live foods such as glass worms, brine shrimp, and bloodworms. However, do remember that if it is placed in a tank with other breeds, its feeding pattern needs to be monitored, as other ravenous fish can consume their share of food easily. This breed will not fight for its share as it is easily intimidated, and therefore, will remain hungry. Breeding While trying to breed them, it is best to place them in a tank separate from other breeds. The best way is to raise a minimum of six of these fish at a time. They spawn better when given a little privacy, so place a few bunches of plants in the tank so they can spawn behind them. Maintain dim lights in the tank if you wish the fish to spawn. The water temperature required for their breeding varies from 79 to 82 °F (26 - 28 °C). The female will lay almost 2,000 eggs on areas below the plants or on broad leaves. These eggs hatch in three days and can be fed brine shrimp and commercial fried food. The lifespan of this fish breed is about 8 - 10 years, if you take care of it well. So, you can easily find a lifelong pet in this fish, and watch it grow along with you.