Prionotos Cory

Geographical Origin and Habitat: Species endemic to southeastern Brazil, found in mountainous river systems flowing into the Atlantic. Frequents rapids, streams with mixed sandy and pebbly substrate, shaded by the jungle and refreshed by strong and turbulent currents rich in oxygen.

Taxonomy and Morphology: Closely related to but distinct from Corydoras, ascribed to the Scleromystax genus. Shows the elegant "scleromystax" conformation: slender body shape, touches 6.5 cm (2.5 inches), boasts a moderate snout and decisively elongated masculine dorsal fin (although not aberrant like macropterus).

Social Behavior: Fundamental schooling needs (6-8 specimens) to reassure it. Males set up delicate hierarchical disputes without injuring themselves or violently chasing each other. Less active in daytime searching, loves to stop for long stretches on round pebbles oriented upstream.

Coloration and Sexual Dimorphism: Clear and irrefutable dimorphism. Metallic sand-colored male with scales densely marbled with molten black, yellow belly, a marked dorsal extension, and expanded opercular facial lobes. Female extremely stocky, short, with stubby fins and a rather dull brown coloration.

Aquarium Setup: Moving river biotope: essential insertion of additional circulation pumps (River-manifold). Build terraces of large smooth river stones sunk in dense inert sand. Rejects visual isolation without large protective green fronds.

Diet and Feeding: Benthic hunter. Offer sinking meals (crumbled bottom tablets). Prefers fresh/frozen over dry baits: feed it regularly in the evening and morning with large rations of mysis, tubifex, and giant, crunchy bloodworms.

Water Quality: Not a true tropical fish. Likes constantly mitigated subtropical water (temperature 20-25°C / 68-77°F). Slowly suffocates and loses vitality over 26°C (79°F). The weakly acidic or neutral pH fluctuates around 6.0 - 7.2, associated with medium/low hardness and drastic water changes (no ammonia).

Compatibility and Cohabitation: Being a peaceful creature, it lives gracefully with small South American dither fish (Aphyocharax, Black Widow Tetras). Defenseless victim not to be combined under any circumstances with large Ancistrus, Loaches, and dominant Cichlids that are frantic devourers of food from the ground.

Aquarium Breeding: Is triggered, similarly to Corydoras, by sudden drops in temperature induced by decisive water changes with cool RO. Rapid T-crossings lead to the spawning in full current of large tenacious eggs sealed to the glass. Very high degree of parental cannibalism.

Risks and Diseases: Asphyxiation due to warm tanks (27+ °C) causes lethal stress or parasitic collapses. Faces deadly atrophy and necrosis of the whiskers in case of abrasive bottoms (non-ceramized quartz). Suspend/avoid Copper and Malachite treatments (lethal hypersensitivity).