Twig Catfish

Farlowella acus is the type species of the twig catfish genus and one of the most well-known members of Loricariidae. Found in slow to moderately flowing rivers and flooded forest zones across the Amazon basin, it spends most of its time clinging to driftwood, plant stems, and broad-leaved plants, rasping biofilm and soft algae. Its extraordinary elongated body, covered in bony plates and coloured in shades of brown and tan, renders it nearly indistinguishable from a fallen twig.

In the aquarium, Farlowella acus requires excellent water quality and a mature tank with abundant wood and plants. It is sensitive to nitrates and does poorly in newly established systems. Despite appearing delicate, it is a rewarding species that will breed in captivity if conditions are right, with males guarding egg clusters laid on flat surfaces or plant leaves.

Twig catfish are wholly peaceful and can be kept with small, non-boisterous community fish. They should never be housed with fin-nippers or robust cichlids. A varied diet including high-quality algae wafers, blanched zucchini, and spirulina-based foods is essential for long-term health.

Water: 23–28°C, pH 6.0–7.5, soft to moderately hard (GH 2–12); sensitive to nitrates — keep below 20 ppm. Tank: 100 L minimum; provide driftwood, broad-leaved plants and dappled lighting; avoid strong turbulent flow. Feeding: Algae wafers, blanched zucchini and cucumber, spirulina tablets; supplement with biofilm on wood. Breeding: Egg-layer; male guards eggs on flat surfaces; raise fry in a separate vessel with gentle flow. Compatibility: Peaceful community fish only — tetras, small rasboras, dwarf cichlids; avoid fin-nippers and aggressive species.