Endemic to the upper and middle Río Orinoco watershed in Colombia (departments of Meta, Casanare, Arauca, Vichada, and Guainía) and Venezuela (states of Amazonas, Apure, Guárico, and Bolivar). It has been collected from several major tributaries including the ríos Atabapo, Guaviare, Inirida, Ventauri, Meta, Cinaruco, Arauca, Apure, Capanaparo, and Caura.

Apparently favours minor tributaries, smaller rivers, oxbows, and flooded forests rather than main river channels.

It occurs throughout the vast llanos regions of Colombia and Venezuela, and in the latter country is often associated with habitats known as morichals which tend to contain transparent, clear water and sandy substrates, often with dense growth of aquatic plants or riparian vegetation among which the fish take shelter.

In other parts of its range it has been collected from both flowing blackwater habitats and still floodplain lakes, while the majority of rivers and wetlands across its range are subject to extreme flooding during the annual rainy season.

One example of a natural habitat is the Río Cinaruco, a low nutrient, blackwater tributary of the Orinoco in southwestern Venezuela which comprises a meandering river channel with numerous interconnected lagoons and floodplain lakes.

The latter two biotope-types feature reduced water flow, increased turbidity and temperature, a greater accumulation of leaf litter, and higher densities of zooplankton than the main channel.

Tucanoichtys tucano