Red Shouldered Severum (Heros sp. Rotkeil)

Geographic Origin and Biotope: Restricted area of the Rio Nanay and Amazon River systems in Peru. Populates slow-flowing channels and forest lakes (Oxbow lakes), swimming among intricate submerged forests.

Taxonomy and Morphology: Red Shouldered Severum / Rotkeil Severum (Heros sp. "Rotkeil"). The species is not yet formally described (Sp.), but it is the most iconic Severum for advanced aquaristics, due to its oval and majestic build.

Social Behavior: Regal and extremely tolerant. Forms fluid hierarchies and spends most of its time picking at debris or exploring roots. Maintains a calm demeanor that appeases (Dither) even the most nervous tankmates.

Coloration and Sexual Dimorphism: The "Red Shoulder" (Rotkeil = Red wedge in German). The adult body is olive broken by strong vertical black bars, but it is the crown and the area behind the gills, blazing bright red-orange, that gives it its name. The male is larger and has a vermiculated face.

Aquarium Setup: Huge aquariums (150-180 cm / 60-70 inches). The layout must include endless forests of tortuous trunks and smooth branches intertwined in free water, recreating the fallen branches of the Amazon. Plants forbidden (will be eaten). Light attenuated by floating plants (which they will graze from below).

Diet and Feeding: Essentially Herbivorous (Grazer). Feeding it only proteins and dry feed causes fatal intestinal ulcers (Bloat). Requires peas, blanched lettuce, zucchini, spirulina and only sporadically frozen krill or bloodworms.

Water Quality: Less delicate than its Blackwater cousins (Notatus or Liberifer), it accepts dechlorinated tap water as long as it is kept soft and warm (28°C / 82°F ideal). High nitrates will quickly lead to deterioration of the barbels and caudal fins.

Compatibility and Tankmates: Ideal companion for almost any Amazonian fish over 5 cm (2 inches): Discus (they are perfect companions for them), Geophagus, expensive Loricariids (L046, L134). Must be kept away from true predators.

Aquarium Reproduction: Exclusive pairs on smooth substrate (Substrate Spawners). They maniacally sweep a smooth root (or the glass) and defend the thousands of eggs by lashing the water. The young will graze on the parents' body mucus, just like Discus do.

Risks and Diseases: Dropsy from malnutrition. Novice hobbyists mistake them for predators feeding them beef heart to make them grow, condemning them to intestinal death within months.