Common Metynnis

Adults grow up to 15–18 cm in length, characterized by a high, laterally compressed, rounded body. Their coloration is predominantly silver, and their fins and tail remain translucent. Outwardly, Metynnis hypsauchen is almost indistinguishable from the Silver Metynnis, except for a small dark spot above the eye. During the breeding season, males acquire a darker coloration and are distinguished by a reddish anal fin.

These fish are native to South America, where they are widely distributed throughout most of the continent's tropical rivers. They can be found from Guyana to Paraguay, including the vast Amazon River basin. They prefer to inhabit areas of rivers where aquatic vegetation is particularly dense.

It is recommended to keep them in a group of at least 4–5 individuals. These fish are peaceful towards other large species but can pose a threat to smaller fish. The Common Metynnis prefers to inhabit the middle and upper layers of the water, so fish that stay closer to the bottom, such as Plecostomus and Armored Catfish, would make good tank mates.

Optimal conditions for keeping these fish include warm, soft water with low hardness values. For a group of 4–5 individuals, an aquarium of at least 300 liters will be required. When decorating, it is important to provide hiding places created from dense thickets of plants. However, it should be noted that the Common Metynnis can damage the soft parts of aquatic plants. Therefore, it is recommended to choose fast-growing species with tough leaves or use artificial vegetation. Lighting should be subdued. Aquarium maintenance follows a standard schedule, which includes weekly partial water changes with fresh water (maintaining the same pH and dH values), regular removal of organic waste, cleaning the tank walls of algae, and caring for decor elements as needed, as well as equipment prophylaxis. The diet should be based on foods with a high content of vegetable fibers or additional plant supplements, such as flakes or granules. They also readily accept live or frozen foods, such as bloodworms or brine shrimp. It should be noted that these fish may eat smaller aquarium inhabitants, including fry.

The basis of the daily diet should be foods rich in plant components, or additional plant supplements in the form of flakes or granules. These fish also readily accept live or frozen foods, such as bloodworms and brine shrimp. However, it should be noted that they are capable of eating smaller tank mates and fry. It is advisable to keep a group of 4–5 individuals, as they are peaceful towards large species, but small fish may be at risk. The Common Metynnis primarily inhabits the middle and upper water layers, so good companions would be fish that prefer a bottom-dwelling lifestyle, such as Plecostomus and Armored Catfish.

Spawning usually occurs more frequently in soft, acidic water at a temperature of about 28°C. During this period, males acquire a darker coloration, and red hues appear on their chest area. After a brief courtship, the fish lay several dozen eggs, scattering them over the substrate surface without forming a distinct clutch. As a rule, adult individuals do not eat their own eggs. However, other aquarium inhabitants may gladly feast on them. To save the fry, it is recommended to transfer the eggs to a separate tank. Fry hatch approximately three days later. Initially, they feed on the contents of their yolk sac, and then begin to actively swim in search of food. Specialized powdered foods and suspensions for juvenile aquarium fish are used to feed them.

Most diseases in these fish are often associated with unsuitable keeping conditions. If the first signs of illness appear, you should first thoroughly check the water parameters and hydrochemical composition. It is necessary to normalize all indicators, and only then proceed with treatment.

When choosing a Common Metynnis, preference should be given to individuals with clean, shiny scales without visible damage, ulcers, or white film. A healthy fish should be active, exhibit schooling behavior, and show no signs of emaciation. Avoid specimens that isolate themselves, appear sluggish, or have deformed fins, as this may indicate stress or hidden diseases. Given the timid nature of the species, fish in the store may show excessive caution, making sudden movements when a person approaches, which is a normal reaction and not a sign of illness.