Filament Cory

Geographic Origin and Biotope: Endemic to the Corantijn River basin in Suriname (South America). Inhabits slow, clear forest streams, on sandy bottoms partially covered by carpets of fallen leaves (leaf litter) in slow decomposition.

Taxonomy and Morphology: Of medium-small size, reaches a maximum of 4.5 cm (1.8 inches). The name "filamentosus" derives from an exclusive peculiarity of adult males: the dorsal fin has an extremely elongated first ray in the shape of a filament, which sometimes exceeds the height of the body.

Social Behavior: Strictly peaceful and social. To see it foraging serenely on the sand, it must be kept in schools of no less than 6 individuals. Extremely static if kept alone or in over-illuminated tanks without protective vegetation.

Coloration and Sexual Dimorphism: Dark beige-gray base color. Irregular black spots dot the head and flanks, with a black shading at the base of the dorsal. Dimorphism is striking: the male sports the filamentous extension of the dorsal, while the female lacks it, but appears much rounder and more massive.

Aquarium Setup: Substrate imperatively in fine sand to preserve the short barbels. Requires abundant provision of hiding places created by branches (red moor wood), smooth rocks, and abundant vegetation (Cryptocoryne or ferns). The water should have medium surface currents.

Diet and Feeding: Hunter of benthic microfauna. A high-quality diet with carnivorous bottom wafers to be administered when the lights are off is indispensable, in combination with tiny live/frozen larvae (Daphnia, Brine shrimp, and Grindal worms).

Water Quality: Moderately delicate species if exposed to accumulation of nitrogenous compounds. Temperature 22-26°C (72-79°F). Low hardness (GH 2-12) and sub-acidic pH (6.0 - 7.2). Mandatory weekly partial water changes with tempered water.

Compatibility and Tankmates: Excellent inhabitant for small peaceful South American tanks. Compatible with small tetras (Paracheirodon, Nannostomus), dwarf loricariids (Otocinclus). Absolutely avoid predatory loaches and large cichlids.

Aquarium Reproduction: Very complex. Stimulable by imitating rainy seasons (drastic thermal drops and ultra-protein diet). Eggs laid singly among lush mosses (Taxiphyllum). The long dorsal appendages of the males are used in the courtship ritual.

Risks and Diseases: Very high risk of fatal ulcerations to the whiskers if kept on sharp gravel. Severe sensitivity to Aeromonas pathologies on unhygienic bottoms (siphon regularly). Intolerant to copper treatments or preventive addition of salt.