Spotted Metynnis

Adult specimens of this fish reach a length of about 15 cm. Their body is characterized by a large, disc-shaped form, strongly compressed laterally. The coloration is predominantly silvery, adorned with numerous rounded spots. During spawning, males acquire reddish hues on the lower part of their belly. Among other distinguishing features are the elongated first rays of the anal fin, resembling a petal, and a prominent black spot behind the gill cover, standing out against the general pigmentation.

Its natural habitat is the waters of South America, specifically the Guaporé River basin, which is one of the tributaries of the upper Amazon. The species' distribution covers territories from Bolivia to the western regions of Brazil, including the border areas of these countries. The Spotted Metynnis is found throughout the entire course of the river.

These fish prefer to live in a school or a small group, consisting of at least 6 individuals. When kept alone, they can become excessively aggressive and nervous. They are compatible with fish of comparable size from among South American cichlids, catfish, characins, and also cyprinids. Small fish species are not recommended to be kept with them, as they will inevitably be perceived as food.

For a school of 6–8 individuals, the optimal aquarium volume starts from 400 liters. When setting up the tank, it is important to provide ample open swimming space, complemented by shelters. Branched snags, imitating tree roots, are ideal. The substrate can be stony, with the inclusion of large boulders. Live aquatic plants are not recommended, as they will quickly be eaten. If there is a desire to add "greenery," artificial plants will be a good alternative. The Spotted Metynnis has high demands regarding its habitat conditions. It requires very clean, well-aerated flowing water. It is advisable to use a powerful internal filter system that not only cleans the water but also creates the necessary current for these fish. In some cases, additional aerator diffusers may be required. In addition to equipment, regular execution of specific aquarium care procedures is of great, and sometimes key, importance: timely removal of organic waste (food remnants, excrement), weekly partial water changes (30–50% of the total volume) with fresh water, and other measures.

Being an omnivorous species, this fish feeds on almost any available food. Its diet includes small fish, insects, worms, as well as algae, aquatic plants, and even fallen fruits and seeds. In a home aquarium, it is important to provide a varied diet, including both live and frozen foods (such as earthworms, shrimp meat, mussels), and plant supplements (for example, blanched pieces of lettuce, peas, zucchini, fruits). There are also specialized commercial foods developed to meet all the dietary needs of such fish.

As of the preparation of this article, the authors have not been able to find confirmed information about the successful breeding of this species in artificial aquarium conditions.

This fish is distinguished by its unpretentiousness and hardiness. Health problems usually arise due to injuries, inadequate nutrition, or unsuitable water composition. When signs of illness appear, such as lethargy, changes in body shape, or loss of appetite, it is often sufficient to normalize the keeping conditions for the fish's body to cope with the problem on its own. However, in some cases, medication may be required. More detailed information on symptoms and treatment methods can be found in the "Diseases of Aquarium Fish" section.

When purchasing, choose active individuals that show interest in food and swim in the water column. Avoid fish with signs of fin damage, film on scales, or an unnaturally swollen belly. It is important to consider that in stores, these fish are often kept in conditions that do not meet their needs, so carefully assess the overall health of the entire group in the aquarium. Since the species is schooling, it is recommended to acquire a group of six or more individuals at once to reduce stress levels and prevent aggressive behavior.