Diadem Cichlid (Aequidens diadema)

Geographic Origin and Biotope: Found predominantly in the upper Rio Negro and Orinoco basin in South America. Lives along calm sheltered river banks or temporary "lagoons" rich in forest tannins (blackwater).

Taxonomy and Morphology: Diadem Cichlid (Aequidens diadema). A robust Cichlid with a moderately high back (classic "Acara"). Like most Aequidens, it has a short snout and a mouth with strong lips for hunting and manipulating substrates.

Social Behavior: Relatively peaceful but expresses character and strong territoriality during maturity or reproduction. Imposes itself in the tank not by impetuosity, but by "size" and pride. Enjoys wide open spaces among the woods.

Coloration and Sexual Dimorphism: Beige-gold or silvery background crossed by a large dark bar or spot mid-body. Develops sparkling turquoise and reddish reflections on the flanks and unpaired fins. Adult males display filamentous extensions on the dorsal and caudal, with more vibrant colors.

Aquarium Setup: Tank for medium Cichlids (120 cm / 48 inches). Fine sand, many large oak or catappa leaves that yield amber in the water, massive intertwined roots (Spiderwood/Bogwood) to provide visual divisions. Very robust plants (Echinodorus, Anubias) tolerate its presence.

Diet and Feeding: Omnivore (Micro-Predator). Gorges on insects in nature. Greedily eats large high-quality flakes, floating or sinking protein pellets, frozen krill and mosquito larvae. Vary the diet to keep the coloration bright.

Water Quality: Prefers warm (24-28°C / 75-82°F) and soft waters. An efficient filtration system is indispensable given the notable organic impact typical of moderately large South American cichlids.

Compatibility and Tankmates: Excellent fish for robust "Community tanks": coexists excellently with large Tetras (e.g. Columbian, Black Widow), medium-sized Plecostomus, and other not overly aggressive South American cichlids (Geophagus or Mesonauta). Will eat too small characins.

Aquarium Reproduction: Open substrate spawners. They form granite pair bonds. The female lays up to 300 eggs on smooth rocks or large cleaned leaves. Both parents guard the offspring, aggressively dispersing any tankmate.

Risks and Diseases: Subject to severe malnutrition or stress (with immediate loss of iridescent reflections) if harassed by dominant "Tank buster" Cichlids like Flowerhorns or Red Devils.