Farlowella Catfish Care Guide: Tank Setup, Diet & Breeding Tips

Species Overview#

The Farlowella catfish (Farlowella acus) is the fish most likely to fool a guest into thinking your tank is decorated with sticks. Long, pencil-thin, and the color of weathered wood, this South American suckermouth lives by camouflage — pressing itself against driftwood and broad leaves where, motionless, it disappears completely. Farlowella have been a curiosity in the hobby for decades, but they remain firmly niche because they need exactly what most beginner tanks lack: pristine water, a thick mat of biofilm, and tank mates patient enough to leave the food alone long enough for a slow grazer to find it.

This is the same species commonly sold under the name Twig Catfish. The two names describe one fish, and the care requirements are identical regardless of which label your local store uses.

Adult size

6-8 in (15-20 cm)

Lifespan

10+ years

Min tank

30 gallons

Temperament

Peaceful

Difficulty

Intermediate

Diet

Herbivore

Natural Habitat & Origin#

Farlowella acus comes from the Orinoco River basin and surrounding slow-moving waterways across northern South America. The water there runs warm, soft, and acidic — stained the color of weak tea by tannins leached from a constant rain of fallen leaves and submerged wood. Visibility is often poor, current is gentle, and the riverbed is a chaos of branches, roots, and decomposing plant matter coated in algae and microbial film.

The fish has evolved to match this environment in every detail. Its long, narrow body lies flat against horizontal branches; its mottled brown coloration breaks up its outline against bark; and its specialized rasping mouth is built to scrape biofilm from the surface of soaked wood. A bare-bottom tank with bright lighting and clean glass is, biologically speaking, the opposite of where this fish wants to live.

Appearance & Size#

A mature Farlowella looks more like a piece of driftwood than a fish. The body is extremely slender — sometimes less than half an inch wide on a 7-inch adult — and tapers from a flattened head with a pointed rostrum down to a long, whip-like tail. The dorsal surface ranges from light tan to dark brown with darker speckling along the flanks; the ventral side is paler. Fins are mostly transparent except for the dorsal, which usually carries a darker leading edge.

Adults reach 6 to 8 inches in length, with the rostrum accounting for a notable portion of the total. Despite the size, the fish is so thin that it occupies far less visual space in a tank than a chunkier catfish of the same length. Sex is hard to call until fish mature past 3 to 4 inches; males then develop small odontodes (bristle-like spines) along the edges of the rostrum, while females stay smooth-snouted.

Lifespan & Difficulty Rating#

Well-kept Farlowella commonly live 10 years or more in a home aquarium, with some specimens reportedly reaching 12 to 15. The species earns an intermediate difficulty rating not because it is fragile in any one dimension, but because it stacks several small sensitivities — soft acidic water, low nitrate tolerance, slow feeding, easy starvation, copper sensitivity — that combine into a fish that does badly in the average community tank but thrives for keepers who plan around it.

Water Parameters & Tank Requirements#

Farlowella are not difficult to keep alive when their water is right. Almost every problem traces back to one of three things: water that is too hard or alkaline, nitrates allowed to drift above 20 ppm, or a tank too young to support a biofilm grazer.

Ideal Water Parameters#

Aim for temperatures between 75 and 82°F. The species tolerates the warmer end of this range well, but stability matters more than the exact target. pH should sit between 6.0 and 7.0 — soft and slightly acidic, mirroring the tannin-rich blackwater conditions of their native rivers. Hardness in the soft to moderately hard range (under 12 dGH) keeps fish comfortable.

Ammonia and nitrite must read zero. Nitrate is the parameter most keepers underestimate: Farlowella decline visibly when nitrate stays above 20 ppm for extended periods, and chronically high nitrate is tied to the rostrum erosion that plagues neglected tanks. A weekly water change in the 25 to 30 percent range, with conditioned soft water, keeps levels in safe territory.

Minimum Tank Size & Layout#

A single Farlowella needs at least 30 gallons of well-aged tank, and a 40-gallon footprint with extra horizontal swimming space is more comfortable. Tank length matters more than depth — these fish use the long axis of the tank to glide between perches, and tall narrow tanks waste space they cannot use.

Furnish the tank like an Amazonian backwater: heavy driftwood pieces angled to give horizontal landing surfaces, broad-leaved plants like Echinodorus or Anubias for resting on, and a layer of botanicals (Indian almond leaves, alder cones, dried oak leaves) that stain the water faintly tea-colored and feed the biofilm Farlowella grazes. Lighting should be dim or shaded by floating plants — bright lights stress the fish and discourage the biofilm growth they need.

Filtration & Flow#

Farlowella need clean, oxygen-rich water but cannot handle strong current. The combination is best met with a sponge filter (or two, on tanks 40 gallons and up) plus either a baffled hang-on-back filter or a canister filter with the spray bar aimed at the back glass to diffuse flow. The goal is gentle but constant water movement and high dissolved oxygen, not a torrent that pins a slim-bodied fish against the glass.

If you can see the fish struggling to hold position on driftwood or being pushed around by the outflow, the flow is too strong. Add baffles, redirect the output, or downsize the pump.

Substrate & Décor Choices#

Use fine sand. Coarse gravel and sharp décor are bad matches for Farlowella because the fish drags its delicate rostrum across surfaces while feeding, and abrasive substrates wear down the snout over time, opening the door to bacterial infection. Smooth river rocks, soft driftwood pieces (Malaysian, mopani, or spider wood, well-soaked first), and broad-leaf plants give the fish appropriate perching surfaces without risking damage.

Indian almond leaves are particularly useful. They release tannins that mildly soften and acidify the water, leach mild antimicrobial compounds, and slowly grow biofilm on their undersides — providing both habitat and food. Replace leaves every two to four weeks as they break down.

Diet & Feeding#

Farlowella are obligate herbivores in practice. They will pick at the occasional protein source, but their digestive system is built around a steady stream of plant matter and microbial film, and pushing protein-heavy foods on them causes bloating and long-term gut problems.

Natural Diet & Grazing Behavior#

In the wild, Farlowella spend most of their active hours rasping at biofilm, soft algae, and aufwuchs — the layer of microorganisms, diatoms, and tiny plant matter that coats every submerged surface in a healthy river. They graze slowly and methodically, working a single piece of wood or leaf for hours before moving on.

This is not a fish that competes for food. It does not dart into a feeding cloud. It does not chase pellets across the substrate. It finds its food by patient, head-down grazing, which is exactly why it loses every food fight to faster tank mates.

Recommended Foods in Captivity#

Build the captive diet around algae wafers and blanched vegetables, supplemented by the natural biofilm in the tank. A solid rotation:

• Algae wafers (Hikari Algae Wafers or similar) two to three times per week, dropped after lights-out to give the Farlowella time to find them
• Blanched zucchini, cucumber, or spinach twice a week, anchored with a vegetable clip or a fork pushed into the substrate
• Spirulina-based sinking pellets as occasional variety
• Soft, well-grazed driftwood as a permanent dietary fixture, providing fiber and biofilm

Avoid heavy protein foods — bloodworms, beef heart, high-protein cichlid pellets — as a regular offering. They are not just unnecessary for this species; they actively cause digestive trouble.

Feeding Frequency & Common Mistakes#

Feed in the evening, shortly after lights-out. Farlowella are most active at dusk and night, and food dropped during peak daylight is often eaten by tank mates before the catfish even leaves its perch. Drop blanched vegetables in one corner of the tank and check in 30 to 60 minutes — a Farlowella will usually be wrapped around the food by then.

The most common feeding mistakes are underfeeding (assuming "algae eater" means the fish doesn't need food), overfeeding protein, and feeding only during the day. The second-most-common is letting fast tank mates eat everything before the Farlowella arrives. If you have aggressive eaters, target-feed the catfish in a covered area or use a feeding ring placed near its preferred perch.

Tank Mates & Compatibility#

Farlowella are peaceful, slow-moving, and easily outcompeted at feeding time. Tank mate selection is the single biggest variable in long-term success after water quality.

Ideal Community Partners#

The best companions are small, peaceful fish that occupy different parts of the tank and don't bully a slow grazer. Good options include:

• Small tetras like neon, cardinal, ember, and rummy-nose tetras
• Corydoras catfish — they share substrate space without territorial conflict
• Dwarf cichlids like German blue rams and apistogrammas, in tanks large enough to accommodate both territories
• Peaceful rasboras like harlequin, lambchop, and chili rasboras
• Otocinclus — another peaceful biofilm grazer with similar requirements; they share the cleaning duties without competing for cave space

Species to Avoid#

Skip silver dollars and other large herbivores that strip plants and food before the Farlowella can reach it. Avoid African cichlids entirely — wrong water chemistry, wrong temperament, wrong everything.

Intraspecies Behavior#

Farlowella are not strongly schooling but tolerate their own kind in groups when space allows. Mature males can become territorial with each other, particularly around chosen spawning perches, so keep a single male with two or three females rather than multiple males in the same tank. Females coexist peacefully and a small group displays more natural grazing behavior than a solo specimen.

Breeding Farlowella Catfish#

Farlowella breed in the home aquarium with regularity once a healthy pair settles into a stable tank. Hobbyist breeding is the main reason quality captive-bred specimens are increasingly available.

Sexing Males vs. Females#

The reliable sex marker is the rostrum (snout). Mature males develop small odontodes — bristle-like spines — along the lateral edges of the rostrum, giving the snout a slightly fuzzy or serrated outline when viewed from above. Females stay clean-edged and smooth. The difference is hard to see until the fish reach 3 to 4 inches; below that size, sexing is unreliable.

Males are also typically slimmer through the body than gravid females. If you are buying from a store and want a known pair, ask the staff to net likely candidates so you can check the rostrum in the bag.

Spawning Conditions & Egg Care#

A bonded pair will often spawn without prompting in a stable, well-fed tank. To encourage spawning, perform a slightly larger water change with cooler, soft water — a 30 to 40 percent change with water 3 to 5°F below tank temperature mimics the seasonal rains that trigger spawning in the wild.

The female lays a tight cluster of 30 to 80 eggs on a flat, clean surface — typically a broad Echinodorus leaf, a section of glass, or a smooth piece of driftwood. The male takes over guarding immediately, fanning the eggs with his fins and chasing off intruders for the 7 to 10 days until hatching.

Raising Fry#

Newly hatched fry remain on the spawning surface for a few days, absorbing their yolk sacs, then become free-swimming and immediately ready to graze. They survive on biofilm and microalgae from the start — no live food cultures required, which makes them genuinely easier to raise than most catfish fry.

Survival depends on water quality. Fry are more sensitive to ammonia spikes and unstable parameters than adults, so move them to a dedicated rearing tank with mature sponge filtration and plenty of biofilm-coated surfaces. Daily small water changes and supplemental feeding with crushed spirulina and finely ground algae wafers keep them growing. Move grown fry back to the main tank or trade them through local clubs once they reach 1.5 inches.

Common Health Issues#

Farlowella are hardy when their water is right but show specific vulnerabilities tied to their delicate body shape and scaleless skin.

Rostrum Erosion & Bacterial Infections#

The most common Farlowella ailment is rostrum erosion — gradual wearing away or ulceration of the long pointed snout. Causes are usually environmental: abrasive gravel, sharp décor, prolonged exposure to high nitrates, or constant pressure from territorial tank mates that force the fish to relocate frequently. Once the rostrum is damaged, secondary bacterial infection follows quickly.

Prevention is easier than cure. Use fine sand, smooth décor, keep nitrate under 20 ppm, and ensure tank mates leave the fish in peace. If erosion is already happening, improve water quality immediately, switch to softer botanical-rich conditions (Indian almond leaves help), and treat any visible infection with a gentle antibiotic dosed at half strength.

Sensitivity to Medications & Copper#

Farlowella are scaleless-adjacent and react badly to many common aquarium medications. Copper-based treatments — used routinely for ich, velvet, and external parasites — are highly toxic to Farlowella even at therapeutic doses for other fish. If your community tank needs copper treatment, move the Farlowella to a hospital tank first.

For other medications, dose at half the package recommendation and watch the fish closely for signs of distress (gasping, loss of equilibrium, increased mucus production). Praziquantel for flukes and gentle aquarium salt at low concentrations are generally safe; formalin and most antibiotics should be approached cautiously.

Starvation Risk#

Sunken belly is the calling card of an underfed Farlowella, and it is one of the fastest-progressing problems in this species. The fish appears to lose weight overnight once its food intake drops below maintenance, and once the abdomen is visibly concave the fish is often too far gone to recover even with intensive feeding.

Watch the belly profile every time you observe the tank. A healthy Farlowella has a softly rounded ventral line; a starving one has a flat or concave one. If you see the early stages of weight loss, target-feed blanched vegetables in the evening and consider whether tank mates are stealing food before the catfish reaches it.

Where to Buy & What to Look For#

Farlowella are sometimes available at general fish stores and reliably so at species-focused or aquascaping-oriented shops. Quality varies enormously — a stressed, underfed specimen from a busy chain store starts at a major disadvantage and may not recover.

Healthy Specimen Checklist#

The two highest-priority checks are belly profile and rostrum condition. A flat or concave belly means the fish has been underfed in the store and is starting from a hole; a damaged rostrum suggests poor substrate or aggressive tank mates and predicts bacterial trouble down the road. Walk away from any specimen that fails either test.

Online vs. LFS Sourcing Considerations#

Buying online opens up a wider selection of specific morphs and known captive-bred stock from established breeders, but Farlowella ship poorly. Their long, slim body is fragile in transit, the bag conditions deteriorate fast, and a stressed specimen may take weeks to start eating again on arrival. If you do order online, choose vendors with strong live-arrival guarantees and do not buy in winter without insulated packaging and heat packs.

A local fish store lets you inspect the fish, watch it feed, and start acclimation within minutes. For a sensitive species like Farlowella, the LFS advantage is significant. Ask the store how long the fish has been in their system — a Farlowella that has been settled and feeding for two weeks is a much safer bet than one that arrived yesterday.

For broader context on stocking the right algae crew for your system, the freshwater fish overview covers community planning, and the twig catfish entry shares this same species under its more common shorthand. If you are dealing with a brown algae outbreak, a Farlowella alone will not solve it — the underlying lighting and silicate issues need addressing — but the fish will keep up with the residual film once you fix the cause.

Quick Reference#

• Tank size: 30 gallons minimum; 40+ gallons preferred for groups
• Temperature: 75-82°F (24-28°C)
• pH: 6.0-7.0
• Hardness: Soft to moderately hard (under 12 dGH)
• Nitrate: Under 20 ppm — non-negotiable
• Diet: Herbivore — algae wafers, blanched zucchini, spirulina, biofilm
• Substrate: Fine sand only — no coarse gravel
• Décor: Driftwood, broad-leaf plants, Indian almond leaves
• Tank mates: Small tetras, corydoras, dwarf cichlids, peaceful rasboras
• Avoid: Aggressive plecos, fin-nippers, large cichlids, copper medications
• Sexing: Males show odontodes along rostrum edges; females stay smooth
• Adult size: 6-8 inches (15-20 cm)
• Lifespan: 10+ years
• Difficulty: Intermediate