Otocinclus xakriaba

Otocinclus xakriaba is described from the São Francisco River drainage and is named in honour of the Xakriabá indigenous people of Minas Gerais, Brazil, within whose traditional territory the type locality falls. Like O. travassosi, it is restricted to the São Francisco basin — a geographically isolated drainage with a highly endemic ichthyofauna — and is one of the smallest Otocinclus species, rarely exceeding 3.5 cm.

The São Francisco's upper tributaries, where O. xakriaba is most likely encountered, include clear to lightly turbid streams flowing through tropical dry forest and cerrado vegetation. These streams have varied water chemistry influenced by geology and seasonal rainfall. The species shares the genus-typical biology: social, diurnal, herbivorous grazer of biofilm and soft algae from hard substrates.

For aquarists, O. xakriaba is an exceptionally rare find. It is seldom exported and commands specialist interest for its endemism and diminutive size. Those who obtain it will find its care identical to other members of the genus, though attention to the slightly harder water chemistry of the São Francisco basin may improve long-term health. It makes a fascinating centrepiece for a São Francisco biotope setup.

Water: Soft to moderately hard at pH 6.0–7.5 and 20–26°C; slightly harder water than typical Amazonian otocinclus is acceptable. Tank: 40 litres minimum; a São Francisco biotope with sand substrate, smooth stones, and native plants is ideal. Feeding: Biofilm, blanched vegetables, algae wafers; supplement feeding critical given its very small size. Breeding: Not documented; standard soft-water conditioning approach. Compatibility: Fully peaceful with all nano species and invertebrates.