Farlowella catfish
Farlowella acus
advanced careOverview
The farlowella catfish (Farlowella acus), or twig catfish, is a remarkable oddball: a long, slender, brown fish that looks exactly like a submerged twig and grazes algae from wood and glass. It is beautiful and peaceful, but it is firmly a specialist. Twig catfish are delicate, easily starved, and intolerant of poor or unstable water, so they belong in mature, well-managed tanks kept by experienced aquarists rather than in new setups.
Tank & water
A single fish needs a long, mature tank of at least 120 litres (30 gallons) with plenty of floor and wood surface. Hold 23–27 °C with a filter providing strong oxygenation and gentle-to-moderate flow on soft, well-cycled water.
- Driftwood is essential: twig catfish graze biofilm and rasp on wood — it is not optional decor.
- Mature, algae-friendly tank: they need established surfaces to graze; a sterile new tank starves them.
- Smooth substrate: sand suits them — see best aquarium sand and gravel and the substrate hub.
Feeding
As herbivores, farlowella need a constant supply of plant matter. Grazing algae and biofilm is not enough on its own — offer daily blanched vegetables (courgette, cucumber, spinach) plus quality algae wafers and sinking herbivore food. See our best fish food picks. A visibly thin, sunken belly means it is starving, so err on the side of over-provisioning greens.
Tankmates
Peaceful to a fault, twig catfish suit calm, small communities of tetras, rasboras, dwarf corys and otocinclus, which share its gentle, algae-grazing lifestyle. Avoid fast, greedy or aggressive fish and large plecos that will out-compete it. It ignores tankmates entirely, spending its days clinging motionless to wood.
Frequently asked questions
The farlowella twig catfish is a stunning, tree-branch mimic for the patient specialist. Give it a mature, oxygen-rich tank with wood and a steady supply of greens, and it becomes a long-lived, fascinating resident — but it is no fish for a beginner.
Farlowella catfish — frequently asked questions
Is the farlowella catfish hard to keep?
Yes — it is a specialist, not a beginner fish. It needs a mature, stable, well-oxygenated tank with a steady supply of algae and biofilm, plus supplementary vegetable food. Twig catfish are easily starved and sensitive to poor water, so only add one to an established setup.
Does a twig catfish really eat algae?
It grazes soft green algae and biofilm from wood and surfaces, so it helps, but you cannot rely on algae alone. Once the tank is clean it will slowly starve without daily blanched vegetables and algae wafers to replace the natural grazing.
Can farlowella catfish be kept with plecos?
Cautiously. Large or aggressive plecos will out-compete a gentle, slow twig catfish for food and grazing space. It does far better with small, peaceful tankmates in a tank where it isn't jostled off its food.
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