Filament Cory

Corydoras filamentosus is one of the most distinctive cories in the genus. Adult males develop striking filamentous extensions to the dorsal fin rays — elongated, thread-like projections that add a dramatic flair to an otherwise modestly patterned fish. The body is tan with small scattered spots and a faint lateral stripe, and both sexes display a dark humeral blotch.

Native to Suriname, this species inhabits coastal lowland streams with soft, slightly acidic water and fine sandy substrates. It is a rarely exported species that requires slightly more care than beginner cories due to its preference for clean, soft water and its sensitivity to sudden parameter changes.

In a well-maintained aquarium with stable water quality, C. filamentosus is a rewarding and long-lived fish. Keep in groups of six or more; the display of fin filaments among competing males is particularly impressive. Feed high-quality sinking foods and supplement with frozen or live invertebrates to bring out the best colouration and finnage.