Taxonomy & naming
Farlowella hasemani was described by Eigenmann and Vance in 1917 and is recognised as valid by the Catalog of Fishes (Eschmeyer, CAS). It was later redescribed by Retzer and Page (1997) in their revision of the genus Farlowella. The genus sits within the subfamily Loricariinae, the whiptail and twig catfishes, characterised by their long, depressed bodies and elongate caudal peduncles.
The genus name Farlowella honours William Gilson Farlow (1844–1919), a Harvard botanist; the species epithet hasemani honours the zoologist and ichthyologist John Diederich Haseman (1882–1969), who collected extensively in South America.
Morphology
Farlowella hasemani reaches a maximum recorded length of about 6.5 in standard length (SL). Like other members of its genus, it has the extremely slender, elongate, twig-like body that gives the group its common name, with a long thin snout and a depressed, armoured trunk — an overall form that closely mimics a submerged stick or twig. As in other loricariids, the body is protected by bony plates and the mouth is a ventral sucker.
No information on live coloration patterns or on sexual dimorphism specific to this species has been published in the sources consulted, though male Farlowella in general develop odontodes (small skin teeth) on the snout.
Habitat
Farlowella hasemani occurs in South America, recorded from Pará, Brazil, within the Amazon basin. It is a tropical freshwater, demersal fish. Members of the genus are facultative air-breathers, an adaptation that suits low-oxygen conditions and the slow, warm waters where twig catfishes are often found clinging to wood and vegetation.
Specific data on water temperature, pH, hardness, or depth at the collection localities has not been published in the sources consulted.
Feeding
Farlowella hasemani is a grazer, feeding on algae and aufwuchs — the film of algae, microorganisms, and fine detritus that coats submerged surfaces. It is placed at a low trophic level (approximately 2.5), consistent with a largely herbivorous, biofilm-rasping diet. Detailed analysis of its specific diet has not been published, and finer dietary detail is not asserted here.
Mating
No information on the courtship or mating behaviour of Farlowella hasemani specifically has been published in the sources consulted.
Breeding
No breeding observations specific to Farlowella hasemani have been published in the sources consulted. Twig catfishes of the genus are, in general, egg-depositors with paternal care of clutches laid on hard surfaces, but the reproductive details of this particular species are undocumented and are not asserted here.
In the aquarium
Farlowella hasemani is not commonly identified in the ornamental trade, and no husbandry data specific to this species has been published in the sources consulted. Twig catfishes generally are regarded as delicate, requiring clean, well-oxygenated water, ample wood and plant cover, and a steady supply of grazing surfaces; however, no keeping or breeding account exists for this species to draw on, and none should be inferred as established practice.
Conservation
The IUCN Red List assessed Farlowella hasemani as Data Deficient (DD), with the assessment dated 7 November 2018 (Red List version 2025-2). The Data Deficient listing reflects insufficient information to evaluate its extinction risk rather than evidence of either security or decline.