Hidden-toothed Planiloricaria

Planiloricaria cryptodon is the sole species in the monotypic genus Planiloricaria, placing it among the most taxonomically distinctive loricariid whiptails. Its common name references its cryptic teeth (cryptodon = hidden tooth), which are extremely reduced and nearly invisible, adapted for a specialised feeding mode involving fine organic material from substrates rather than heavy algae scraping. It is native to rivers of the Peruvian Amazon basin, inhabiting shallow sandy or muddy-bottomed river sections.

The body of Planiloricaria cryptodon is remarkably wide and flat even by Loricariidae standards, making it one of the most morphologically extreme members of the family. Its combination of monotypic genus status, extraordinary body form, cryptic dentition, and Peruvian provenance make it an object of fascination for Loricariidae specialists and fish taxonomy enthusiasts alike.

In captivity, this species demands a large, wide aquarium with fine sand, gentle to moderate flow, and excellent water quality. It is rarely imported and any specimens that reach the hobby are eagerly acquired by specialists. Husbandry data is extremely limited and careful documentation of all observations is strongly encouraged.

Water: 23–28°C, pH 6.0–7.0, soft to moderate (GH 2–10); gentle to moderate flow; pristine water quality. Tank: 150 L minimum; wide footprint; large open sand area; avoid all sharp substrates. Feeding: Fine sinking pellets, algae wafers, frozen tubifex; reduced teeth mean soft foods preferred. Breeding: Entirely undocumented; monotypic genus — all captive observations are of value. Compatibility: Peaceful with mid-water and upper-level species; avoid competing sand dwellers.