Myleus lamax

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Myleus lamax, also called Blueberry Silver Dollar, is a South American characin valued for its deep body and bluish coloration. It is associated with the rio Tapajós basin in Brazil and belongs to the group commonly known as silver dollars, generally peaceful and schooling fishes. Its laterally compressed body and active swimming style require a spacious aquarium, efficient filtration, and room for group movement. This species remains uncommon in the aquarium trade, making it best suited to aquarists who can provide stable water conditions and a varied diet.

General species description

Myleus lamax is a freshwater fish in the family Serrasalmidae, related to piranhas but not characterized by the same aggressive predatory behavior. It is best kept in a group and usually occupies the middle levels of the aquarium. Its typical silver-dollar shape combines a deep, strongly compressed body with quick swimming ability. Effective filtration and good oxygenation are important, as is an open swimming area along the front of the aquarium. Because its availability is less consistent than that of common silver dollars, the aquarium should be prepared before purchase.

Geographic origin and biotope

Reference country: Brazil. The species is associated with the rio Tapajós basin in the Brazilian Amazon. It comes from tropical waterways where temperatures are warm and the water may be soft and acidic, depending on the season and location. In the aquarium, clean, well-circulated water with no sudden changes is preferable to stagnant conditions. A layout using roots, shaded areas, and open swimming space can reproduce the main features of the natural setting without restricting movement.

Specific location and local name

The main geographic reference associated with Myleus lamax is the rio Tapajós basin in Brazil. The English trade name Blueberry Silver Dollar is the name most familiar to aquarists. No sufficiently established Brazilian local name is retained here. In stores, identification should ideally rely on the scientific name because several round-bodied, silvery fishes are marketed under broad silver dollar names.

Appearance and physical characteristics

Myleus lamax has a deep, laterally compressed body, typical of fishes known as silver dollars. Its basic silver coloration may show blue to blue-violet reflections, especially under subdued lighting and against a dark background. Fin coloration and body markings can vary with age, health, and maintenance conditions. Its mouth is suited to a diet containing a substantial plant component. A long and wide aquarium is recommended because this active fish uses horizontal swimming space more than narrow shelters.

General diet

Myleus lamax should receive a varied diet with a plant-based emphasis. Main foods may include algae-based pellets or tablets, blanched leafy vegetables, and preparations intended for herbivorous fish. Small portions of frozen or protein-rich foods can supplement the diet but should not become the foundation of feeding. Regular vegetable foods help reduce the risk of nutritional imbalance and suit its grazing behavior. Removing leftovers promptly remains important because excess food can quickly reduce water quality.

Essential data

• Original river: rio Tapajós
• Local name used: Blueberry Silver Dollar
• Origin of the scientific name: Myleus is associated with the Greek word mylos, meaning millstone; lamax refers to the Greek word for throat.
• Etymology of the full name: Myleus evokes the grinding dentition of the genus; lamax refers to the throat.
• Common/vernacular names: Blueberry Silver Dollar; blue silver dollar
• Family: Serrasalmidae
• Subfamily: Serrasalminae
• Name pronunciation: MY-le-us LA-max
• Discovery: Michel Jégu, 1989
• Maximum adult size: about 15 cm
• Water temperature and pH: 24 to 28 °C; pH 5.5 to 7.2
• Watercourse appearance and surrounding vegetation: tropical waterways bordered by Amazonian vegetation, with shaded areas and plant debris
• Typical tankmates: Metynnis hypsauchen, Geophagus altifrons, Satanoperca jurupari, Pterophyllum scalare
• Temperament and behavior: peaceful, active, and schooling; keep in a group
• Water depth: swimming areas within the watercourse; no precise value retained
• Sexual dimorphism: limited; difficult to distinguish outside the breeding period
• Bottom structure and current: variable natural substrate, plant debris, and generally moderate flow

In your aquarium

Success with Myleus lamax depends on a spacious aquarium, an appropriate group, and stable water conditions. Leave a broad open swimming area while adding roots and sturdy vegetation. Frequent plant-based foods, properly sized filtration, and regular water changes are essential. Since this fish is uncommon, carefully checking its identification and condition before purchase is worthwhile.