Aequidens pulcher (Andinoacara)

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Aequidens pulcher (Andinoacara), also called Electric Blue Acara, is a South American freshwater cichlid valued for its bright blue coloration and lively behavior. This aquarium strain emphasizes the species’ metallic blue reflections while retaining the typical territorial nature of acaras. It reaches a moderate size and should be kept in a spacious aquarium furnished with hiding places, sand, and smooth rocks. Relatively hardy and fairly common in the aquarium trade, it is best suited to a community aquarium with larger peaceful fish rather than a small, densely stocked setup.

General species description

Aequidens pulcher (Andinoacara) is a robust, active freshwater cichlid that readily accepts a wide range of foods. The trade name Electric Blue Acara refers to a selectively bred variety chosen for its electric blue coloration, which is more uniform and intense than that of the natural form. The species becomes territorial when a pair forms and during spawning, but it is usually less aggressive than many large Central American cichlids. An aquarium of at least 250 litres is preferable for an adult or a pair, with efficient filtration and regular water changes. The layout should provide broken sight lines, shelters, and open swimming space. Its commercial availability is moderate: it is regularly offered, although availability can vary between suppliers.

Geographic origin and biotope

Reference countries: Colombia, Venezuela, and Trinidad and Tobago. The natural form is associated with river systems in northern South America, including parts of the Magdalena basin and neighboring watersheds. It inhabits rivers, streams, side channels, and quiet areas where the current is slow to moderate. The water may be clear or slightly turbid, with sand, fine gravel, mud, and plant debris on the bottom. Banks are often lined with dense vegetation, roots, and submerged branches. In an aquarium, stable, well-oxygenated water ranging from slightly acidic to alkaline generally reproduces its broad habitat preferences better than extreme conditions.

Precise location and local name

The natural form is reported from northern Colombia and Venezuela, as well as the freshwater systems of Trinidad and Tobago. It is particularly associated with the Río Magdalena drainage and nearby northern South American tributaries. In Spanish-speaking areas, the local name vieja azul is used, while Blue Acara and Electric Blue Acara are dominant in the international aquarium trade. Names may differ from one region to another and can be shared with other blue acaras. To avoid confusion when purchasing, it is best to check the complete scientific name, especially when the fish is sold under a color-based commercial name.

Appearance and physical characteristics

Aequidens pulcher (Andinoacara) has an oval, laterally compressed body covered with shiny scales. The Electric Blue variety displays an intense metallic blue color across the body, fins, and head, with turquoise reflections and darker markings around the eye and fins. The dorsal fin is elongated, while the unpaired fins may show blue or orange edging depending on the strain. Adults generally reach about 15 to 18 cm in aquariums, with a maximum size close to 20 cm. Adult males are often larger and develop more extended fins; however, these differences are variable and less obvious in young fish.

General feeding

Omnivorous with a carnivorous tendency, Aequidens pulcher (Andinoacara) readily accepts quality commercial foods. Its diet can include cichlid pellets, frozen foods such as brine shrimp, mysis, and bloodworms, as well as small prey appropriate for its size. A vegetable component, such as spirulina or a complete prepared food, helps provide variety. Adults are best fed in small portions once or twice daily, with uneaten food removed. A varied diet supports growth and color, while overfeeding can cause obesity and declining water quality. Live foods should come from a reliable source to reduce health risks.

Essential data

• Name of the river of origin: Río Magdalena and associated river systems of northern South America
• Local name used: Vieja azul
• Origin of the scientific name: The genus Aequidens refers to teeth of similar size; pulcher means beautiful
• Etymology of the complete name: Aequidens means equal or similar teeth; pulcher means beautiful; Andinoacara combines a reference to the Andes with acara, a term used for South American cichlids
• Common and vernacular names: Electric Blue Acara, Blue Acara, Acara bleu, Vieja azul
• Family: Cichlidae
• Subfamily: Cichlinae
• Name pronunciation: Aequidens pulcher - ay-kwi-denz pull-ker
• Discovery: Theodore Nicholas Gill, 1858
• Maximum adult size: Approximately 20 cm
• Water temperature and pH: 22 to 28 °C; pH 6.0 to 8.0
• Stream appearance and surrounding vegetation: Slow to moderately flowing rivers and streams with roots, submerged branches, plant litter, and dense bank vegetation
• Typical tankmates: Geophagus steindachneri, Hoplias malabaricus, Pimelodus pictus
• Temperament and behavior: Active and territorial as a pair and during spawning; generally moderately aggressive
• Water depth: Shallow to medium-depth areas of rivers and side channels
• Sexual dimorphism: Males are often larger, with more extended dorsal and anal fins; differences are variable in juveniles
• Bottom structure and flow: Sand, fine gravel, mud, and plant debris; slow to moderate current

In your aquarium

To keep Aequidens pulcher (Andinoacara) successfully, provide a spacious aquarium, clean water, and a structured layout. Sand and smooth rocks help reduce injuries when the fish explores or digs. Pay close attention to the territorial behavior of a pair and avoid very small or overly timid tankmates. Efficient filtration, regular water changes, and a varied diet will help maintain its color and vitality. Under these conditions, the Electric Blue Acara becomes an active, visible, and long-lived fish for a suitable community aquarium.