Porthole Catfish

Dianema longibarbis is an unusually slender and active callichthyid from the upper Amazon drainage in Peru, distinguished from most of its family by its tendency to swim in open water rather than rest on the substrate. The row of bold dark spots along each flank and its exceptionally long barbels give it a distinctive appearance that sets it apart from corydoras and hoplos alike. It is an active, sociable species that benefits greatly from being kept in groups of six or more.

In nature, Dianema longibarbis inhabits slow-moving rivers and flooded forest areas with soft, acidic water. In the aquarium it adapts reasonably well to a wider range of conditions, though it shows best colour and most natural behaviour in warm, slightly soft, filtered water with subdued lighting and good plant cover.

Porthole Catfish are peaceful and mix well with similarly sized tetras, rasboras, dwarf cichlids, and other community fish. They are primarily mid-water swimmers but will scour the substrate occasionally for fallen food. Feed with small sinking pellets, micropellets, and frozen invertebrates such as bloodworm and daphnia.

Water: 22–28°C, pH 6.0–7.5, soft to moderately hard (GH 2–12). Tank: 100 L minimum; planted with open swimming space; fine sand substrate; driftwood for shade. Feeding: Small sinking pellets, micropellets, frozen bloodworm, daphnia, and brine shrimp. Breeding: Bubble nest builder like other callichthyids; rarely bred in captivity; condition with live foods. Compatibility: Peaceful; excellent with tetras, rasboras, and dwarf cichlids in a community planted tank.