Taxonomy & naming
Farlowella nattereri was described by Franz Steindachner in 1910 in a contribution to South American ichthyology based partly on specimens from the Natterer collections held at the Naturhistorisches Museum Wien (Vienna). It belongs to the genus Farlowella Eigenmann & Eigenmann, 1889, subfamily Loricariinae, family Loricariidae. The genus is defined by extreme body elongation, a prominently pointed rostrum, an inferior sucking mouth, and a complete armour of keeled lateral scutes. Farlowella is a large genus with over 30 valid species; alpha taxonomy at the species level is challenging owing to the overall morphological conservatism of the group, and several members were historically confused with one another before systematic revisions clarified their boundaries. Retzer and Page's 1996 monograph on Farlowella systematics is the foundational reference for the genus and provides the diagnostic characters separating F. nattereri from related Amazonian species. The Catalog of Fishes (Eschmeyer, CAS) lists F. nattereri as a valid species. Its name honours Johann Natterer (1787–1843), the Austrian explorer-naturalist who spent nearly two decades collecting natural history specimens in Brazil and whose fish collections became the basis for numerous Steindachner descriptions.
Morphology
Farlowella nattereri displays the typical Farlowella body plan: extreme elongation, a more or less circular body cross-section, and a long, tapered rostrum. The body is uniformly armoured with keeled lateral scutes, and the caudal peduncle is slender with a forked tail. Ground coloration is brown to reddish-brown, typically with a pale mid-lateral stripe running from behind the head to the base of the caudal fin, and variable darker speckling or mottling that enhances the twig camouflage. The precise meristic and morphometric characters distinguishing F. nattereri from other Amazonian Farlowella include details of rostral length, scute counts, and fin-ray counts as documented in Retzer and Page (1996). Maximum standard length is approximately 6.5–7.5 in, though typical aquarium and field specimens are often somewhat smaller. Sexual dimorphism follows the genus-wide pattern: mature males develop elongated odontodes on the operculum, snout edges, and along the pectoral-fin spines; these structures are absent or vestigial in females. Gravid females are noticeably broader in the abdominal region.
Habitat
The type locality and collection records for Farlowella nattereri centre on the upper and central Amazon drainage in Brazil, with material attributed to various tributaries of the main Amazon channel in the states of Amazonas and Pará. The species inhabits slow-flowing to nearly still reaches — shallow backwaters, flooded igapó (blackwater-inundated forest), marginal lagoons, and densely vegetated stream banks where submerged woody debris, root tangles, and aquatic macrophytes are abundant. Water conditions in the Amazon basin where the species is found are typically warm (75–84 °F / 75–84 °F), soft, and acidic to near-neutral (pH 5.5–7.0), with very low dissolved mineral content characteristic of blackwater and whitewater tributaries. The species is not found in fast-flowing channel habitats or oxygen-depleted shallow pools; it favours intermediate-quality habitats where adequate surface exchange maintains dissolved oxygen. Like all Farlowella, it relies on crypsis against woody substrates as its primary anti-predator strategy, remaining motionless for long periods by day.
Feeding
Farlowella nattereri is an algivore and periphyton specialist, like all members of the genus. Its small inferior mouth with fine, spoon-tipped teeth is adapted to gentle scraping of biofilm, diatoms, and soft algae from submerged surfaces rather than to hard substrate rasping. In the Amazon basin it exploits the rich periphyton communities that develop on submerged wood and decaying leaves in slow, nutrient-influenced backwaters. Organic detritus incorporated into biofilm mats is also likely consumed. In the aquarium, the species accepts the standard Farlowella diet: high-quality sinking algae wafers, spirulina-based foods, blanched soft vegetables (cucumber, courgette, spinach), and powdered or micro-pellet foods settled to the substrate surface. It does not compete well with boisterous feeders, and food must be placed near favoured resting areas under dim conditions for the fish to feed confidently. A varied diet enriched with plant-based ingredients promotes long-term health and condition.
Mating
Direct observational data on mating behaviour in wild Farlowella nattereri are not documented in the accessible literature. Breeding behaviour can be inferred from aquarium observations of the genus and from the well-documented pattern in related species. Males select a suitable flat substrate — a broad Echinodorus or Anubias leaf, a smooth length of driftwood, or an artificial slate tile — and court females by closely following them and applying lateral pressure. The female deposits a compact adhesive clutch, which the male fertilises externally and then immediately assumes sole guardianship over. The male fans the clutch continuously, maintaining water movement across the eggs to prevent anoxia and fungal infection. In Amazonian environments, breeding is likely correlated with the hydrological cycle, with the transition from high-water to receding-water conditions — when fish concentrate in remaining pools and food resources increase — potentially serving as a trigger. In aquaria, simulating a wet/dry season cycle through water changes and slight temperature manipulation can replicate these cues.
Breeding
Aquarium breeding records for Farlowella nattereri specifically are sparse in the hobby literature, though the species is presumed to breed in a manner consistent with other Farlowella. The requirements established for the genus generally apply: well-conditioned adults, a planted tank with broad flat leaves and smooth driftwood surfaces, soft acidic to neutral water (pH 6.0–7.2, hardness below 10 °GH), and temperatures of 77–81 °F (77–81 °F). Conditioning is promoted by feeding richly on vegetable matter and occasional small protein-rich foods such as frozen bloodworm, combined with regular partial water changes. The male guards the adhesive egg clutch, which typically numbers between 30 and 80 eggs, fanning it until hatching (approximately 7–10 days). Larvae initially bear a large yolk sac and attach to the substrate; free-swimming grazing begins within 3–5 days of hatching. Early foods for juveniles include powdered spirulina, microfauna on aged wood surfaces, and commercial micropellets. Growth is moderate, and juveniles are sensitive to water-quality deterioration — small, frequent water changes are beneficial during the rearing phase. Data on clutch size and hatch rate specific to this species are not reliably documented in accessible sources.
In the aquarium
Farlowella nattereri is an infrequently exported species and is not considered a common aquarium fish, though it appears occasionally in the trade alongside other Amazonian loricariids. Hobbyists who obtain specimens should provide conditions consistent with Amazonian Farlowella generally: a tank of at least 25 US gal with a long footprint, ample driftwood and tangles, broad-leaved plants such as Anubias and Echinodorus, and floating plants to reduce surface light intensity. Water should be soft and slightly acidic to neutral: pH 6.0–7.2, hardness 2–10 °GH, temperature 75–82 °F (75–82 °F). Gentle filtration without strong turbulent flow is essential — sponge filters or low-flow canister returns suit this species well. F. nattereri is strictly peaceful and entirely unsuitable for tanks with fin-nipping or aggressive species. It is compatible with small characins, dwarf cichlids, corydoras, and other non-aggressive Amazonian fish. Evening feeding with sinking wafers or blanched vegetables placed near resting spots is recommended, as the fish feeds primarily at night. The species can be challenging to maintain long-term in tanks with very bright lighting and frequent disturbance; a quiet, dimly lit setup will show the fish at its best and support health over the long term.
Conservation
Farlowella nattereri has not been assessed by the IUCN Red List and carries a status of Not Evaluated (NE). Its range within the Amazon basin spans one of the most biodiverse freshwater systems on Earth, but also one under increasing anthropogenic pressure. Deforestation in the Brazilian Amazon for agriculture and cattle ranching reduces riparian forest cover and degrades the slow-moving, vegetated marginal habitats that Farlowella species depend upon. Siltation from eroded soils, water temperature increases associated with canopy removal, and agrochemical runoff are all secondary threats affecting many Amazonian small fish. Large-scale hydroelectric infrastructure in the Amazon basin also alters hydrological cycles, affecting seasonal flood-pulse dynamics that drive the species' reproductive behaviour. However, without systematic population surveys specifically targeting F. nattereri, the degree to which these regional pressures affect this particular species cannot be quantified. Collection for the ornamental fish trade is minimal and unlikely to represent a significant threat. The most meaningful conservation measure for this and many other understudied Amazonian loricariids is the protection of intact riparian forest cover and the preservation of natural flood-pulse regimes across the Amazon basin.