Pterophyllum eimekei

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Pterophyllum eimekei is a rare and sought-after form of South American freshwater angelfish, associated with the northeastern region of Peru. Its tall body, elegant fins, and social behavior make it a remarkable cichlid for a large planted aquarium. In aquarium literature, this historical form is treated as a form or historical synonym within the group related to Pterophyllum scalare. This profile concerns wild-collected specimens. In Canada, this strain is offered exclusively by Ton.Fish and remains moderately uncommon, making it less readily available than standard captive-bred varieties.

General species description

Pterophyllum eimekei belongs to the angelfish group, freshwater cichlids recognized by their laterally compressed bodies and highly developed fins. This historical form is valued for its natural appearance and Peruvian origin rather than for captive-bred color selection. It is best kept in a group when young, while adults may form pairs and defend a territory during spawning. Its temperament is usually peaceful, although social ranking and breeding can lead to chasing. A tall, long, well-filtered aquarium suits its body shape best. Avoid tank mates small enough to be swallowed, especially once the angelfish reaches adult size.

Geographical origin and biotope

The form is associated with Peru, in the Amazon basin, particularly the region of the Río Nanay. It comes from calm or moderately flowing tropical waters, often stained by organic matter and bordered by riparian vegetation. The natural habitat includes shoreline areas, backwaters, submerged branches, and places where aquatic or flooded terrestrial plants provide vertical cover. The water is generally soft and acidic to neutral, with a stable temperature. In an aquarium, roots, broad-leaved plants, and moderate lighting recreate this environment better than a brightly lit, bare setup. This strain is wild-collected, so gradual acclimation and close attention to water quality are strongly recommended.

Precise location and local name

The locality generally associated with this form is the Río Nanay area near Iquitos, Peru. In the aquarium trade, it may be sold as a Nanay angelfish, Peruvian angelfish, or simply under its scientific name. Local names used by river communities are not retained here. For aquarists, the locality is important because it distinguishes a natural geographic strain from a captive-bred angelfish whose lineage and origin may be mixed. Since these specimens are wild-collected, careful quarantine, varied feeding, and gradual adaptation to aquarium water are strongly recommended.

Appearance and physical characteristics

Pterophyllum eimekei has a tall, slender, strongly compressed body, with long dorsal and anal fins that create a triangular outline. The pelvic fins are threadlike and the pectoral fins are transparent. Natural coloration is generally silver to gray-brown, crossed by dark vertical bars whose intensity changes with mood, age, and surroundings. The fins may show yellowish or reddish reflections, particularly in well-conditioned fish. As with other angelfish, total height can become considerable, especially when the fins are fully extended. Provide a tank with good water depth, open swimming space, and sturdy plants or vertical roots that serve as territorial landmarks.

General diet

Pterophyllum eimekei is omnivorous, with a clear preference for small animal prey. In the wild, its diet may include small aquatic invertebrates, larvae, and other organisms associated with submerged vegetation. In aquariums, a quality pellet formulated for South American cichlids can be supplemented with frozen foods such as brine shrimp, mosquito larvae, and finely chopped krill. Young fish should receive small frequent portions, while adults benefit from measured meals to prevent obesity. A varied diet supports growth, coloration, and breeding condition. Live or frozen foods should come from a reliable source. The priority is a varied, protein-rich diet, without overlooking the fiber supplied by foods containing plant ingredients.

Essential data

• Name of the source river: Río Nanay
• Local name used: Nanay angelfish; Peruvian angelfish
• Origin of the scientific name: The genus Pterophyllum was created for angelfish; the species epithet eimekei is a dedication to Eimeke.
• Meaning of the full scientific name: Pterophyllum comes from the Greek pterón, meaning “wing,” and phýllon, meaning “leaf,” referring to the fins and leaflike outline; eimekei honors Eimeke.
• Common/vernacular names: Nanay angelfish, Peruvian angelfish
• Family: Cichlidae
• Subfamily: Cichlinae
• Name pronunciation: terr-oh-FILL-um eye-MEK-eye
• Discovery: Ernst Ahl, 1929
• Maximum adult size: About 15 cm in length; up to approximately 25 cm tall including the fins
• Water temperature and pH: 25 to 30 °C; pH 5.5 to 7.0
• Watercourse appearance and surrounding vegetation: Calm to moderately flowing water, forested banks, roots, submerged branches, and dense vegetation
• Typical tank mates: Corydoras agassizi, Hemigrammus rhodostomus, Otocinclus cocama
• Temperament and behavior: Peaceful in a community, schooling when young; territorial as a pair and during breeding
• Water depth: Shoreline areas and sheltered zones of shallow to moderate depth
• Sexual dimorphism: Very difficult to distinguish outside breeding; the genital papilla is broader in a spawning-ready female
• Bottom structure and flow: Sandy or muddy bottom, leaf litter and woody debris; low to moderate flow

In your aquarium

Success with Pterophyllum eimekei depends on a spacious, tall, mature aquarium with effective filtration and a moderate current. Soft, stable, well-oxygenated water, regular water changes, and patient acclimation are essential for wild-collected fish. Keep them in a group while they grow, then watch for tension when a pair forms. A varied diet, a layout with roots and vertical plants, and appropriately sized tank mates will help preserve their condition and natural behavior. This strain, offered exclusively by Ton.Fish in Canada, deserves attentive care.