Duck Catfish

About

The duck catfish (Ageneiosus ucayalensis) is a sizeable South American catfish found across a broad range that includes the Amazon and Orinoco basins, the Guianas, and the upper Paraná system. In the wild it gravitates toward calmer water, swamps and the slower reaches of streams, where it patrols near the bottom hunting fish. It belongs to the family Auchenipteridae, the driftwood catfishes, a group distinguished in part by bony plates on the dorsal surface between the head and dorsal fin, and by the absence of nasal barbels in adults. The duck catfish itself has an elongated, laterally compressed body, a distinctly flattened head with a downward-facing mouth, a deeply forked tail, and an unusually long anal fin running much of the belly's length. Body patterning is variable depending on origin. Fish from blackwater habitats, particularly those from the Guiana Shield, tend to run noticeably darker than individuals from other localities. Despite being listed as beginner-level, the real challenge here is tankmates rather than water chemistry: this is an opportunistic predator capable of taking surprisingly large prey, so it needs to be housed with fish of comparable size. In practice, suitable companions at that scale are mostly limited to large public aquarium setups.