Metynnis Maculatus

Datasheet

Behaviour:

The Spotted Metynnis is not typically aggressive but is only suitable for very large tanks housing robust, similarly-sized tankmates such as cichlids, catfishes, cyprinids, and other characins. In its natural habitat, this species is often seen swimming in large schools, and individual fish can become skittish or even aggressive if kept in insufficient numbers in the aquarium. It is recommended to keep a group of six or more individuals to observe a more natural-looking display and interesting interactions among the fish.

Feeding and Diet:

Spotted Metynnis are omnivorous opportunists, feeding on invertebrates, smaller fishes, algae, fruit, nuts, aquatic and terrestrial plants. In captivity, they should be offered regular meals of live and frozen foods along with high-quality dried products and plenty of vegetable matter. Foods like shelled peas, blanched courgette, spinach, and chopped fruit are suitable additions to their diet. Larger specimens can also consume chopped earthworm, prawn, and mussel, but overfeeding should be avoided.

Reproduction & Dimorphism:

While the reproduction of Spotted Metynnis in aquariums has not been documented, studies have observed their breeding habits in the wild. They exhibit an opportunistic reproductive strategy with a long reproductive period, repeated spawning of small batches of tiny eggs, and a relatively small adult body size. Sexual dimorphism is evident, with males possessing extended anterior anal fin rays, dark spots in the dorsal fin, and dark margins on unpaired fins. Females, on the other hand, have a straight anal fin margin and lack certain aspects of the male's color pattern.

Habitat and Distribution:

The exact range of the Spotted Metynnis species is uncertain, with records indicating its presence from Guyana to the upper and lower Amazon basins in Peru and Brazil. However, it is believed to primarily inhabit the upper rio Madeira, including its tributaries like the rios Beni and Mamoré, and the upper rio Paraguai in Brazil. Significant populations have been reported in the rio Guaporé, which flows through the Pantanal wetland, along with the upper rio Paraguai, connected by rising water levels during the wet season. The type locality of Metynnis Maculatus is the "Rio Guaporé, Mato Grosso, Brazil."

Aquarium Setup:

Maintaining water quality is crucial for the Spotted Metynnis, requiring ample open swimming space. Although decor is not highly critical, a setup with a sandy substrate, driftwood roots, branches, rocks, and boulders can enhance the aesthetic appeal. Avoid using aquatic plants as they are likely to be consumed. These fish are sensitive to organic waste and thrive in clean water, necessitating weekly water changes of 30-50%. Additionally, moderate dissolved oxygen levels and water movement, achieved through powerheads and pumps, are recommended for their well-being.