Taxonomy & naming
Farlowella gianetii was described by Diego J. Ballen, Murilo N. L. Pastana and Ricardo C. Peixoto in 2016, in the journal Neotropical Ichthyology (volume 14, number 3, e160046). The Catalog of Fishes (Eschmeyer, CAS) recognises it as a valid species. It is placed in the subfamily Loricariinae of the armoured-catfish family Loricariidae, and within Farlowella it belongs to the Farlowella nattereri species-group.
The genus Farlowella comprises the elongated 'twig' or 'whiptail' catfishes, instantly recognisable for their extreme body elongation and prolonged rostrum. The original description of F. gianetii also included comparative comments on Farlowella jauruensis from the upper rio Paraguai, helping to clarify the boundaries between superficially similar long-snouted species.
Morphology
Farlowella gianetii reaches a maximum recorded size of about 5 in standard length (SL). In common with the rest of the genus, the body is exceptionally long and thin, tapering to a fine caudal filament, and the head extends forward into an elongate snout — the overall silhouette closely mimicking a submerged twig or stem. The body is encased in the longitudinal rows of bony plates (scutes) typical of Loricariinae.
Beyond these genus-level features and the maximum length, no detailed account of the coloration or sexual dimorphism of F. gianetii has been published in a form suitable to summarise here. As in other Farlowella, mature males may be expected to develop odontodes along the snout margins, but this has not been documented specifically for this species.
Habitat
Farlowella gianetii is known from the rio Xingu basin in the state of Mato Grosso, Brazil — part of the larger Amazon drainage. It is a freshwater, demersal (bottom-associated) fish of tropical waters. The Xingu headwaters are clear-water rivers and streams, and Farlowella generally occur where there is moderate current and abundant submerged wood, root tangles and aquatic vegetation to cling to.
No finer habitat data — specific temperature, pH or microhabitat measurements at the collection sites — has been published for this species, so precise field water parameters cannot be stated here.
Feeding
Like other members of the genus, Farlowella gianetii is an algae-grazer with a low trophic level (estimated around 2.6), feeding by rasping the biofilm — algae, microorganisms and fine detritus — from submerged surfaces such as wood and plant stems. No diet study specific to this species has been published; the assessment follows from its trophic position and the well-documented feeding ecology of Farlowella as a whole.
Mating
No courtship or mating behaviour has been published for Farlowella gianetii. In the genus generally, males guard a spawning surface and develop snout odontodes during the breeding season, but no observations specific to this species have been documented.
Breeding
No breeding account has been published for Farlowella gianetii. Farlowella as a genus are egg-layers in which the male typically guards a clutch of adhesive eggs deposited on a hard surface such as wood, stone or broad plant leaves, but no spawning, clutch size or parental-care data exist for this species in the literature.
In the aquarium
There is no established aquarium record for Farlowella gianetii specifically; it is a recently described species not identified as a regular trade import. Twig catfishes of the genus Farlowella are kept by experienced hobbyists, but they are demanding: they require mature, well-oxygenated, clean water, gentle current, plentiful submerged wood and a steady supply of algae and biofilm, and they fare poorly in newly set-up or under-fed tanks. Any of this general guidance applies only by analogy to the genus, not from documented experience with F. gianetii.
Conservation
The IUCN Red List assessed Farlowella gianetii as Near Threatened (NT) on 16 November 2020, under criteria B1ab(iii)+2ab(iii) — reflecting a restricted range in the rio Xingu basin combined with a continuing decline in the extent or quality of its habitat. The Xingu drainage faces ongoing pressures from deforestation, agricultural expansion and hydroelectric development, all of which can degrade the clear-water stream conditions this species depends on. It is not listed under CITES.