Kurupung

The green line lizard tetra, Iguanodectes spilurus, is a characin found throughout the Amazon, Orinoco, Essequibo and Tocantins river systems. The most widespread Iguanodectes species, it has also been called the 'slender', 'spindle' or 'iguana' tetra, and differs from its congeners in its translucent dorsal and anal fins, lack of a red lateral stripe and prominent dark caudal-fin marking. It is sensitive to poor water conditions.

The barred pencilfish, Nannostomus espei, is a lebiasinid considered endemic to the Mazaruni River system in Guyana. The only member of the genus to show a vertically-barred pattern permanently, it has five dark bar-like markings on each flank where congeners have horizontal stripes. It inhabits sluggish blackwater habitats where pH can be as low as 4.0, and its small size and timid nature suit a tank of its own or diminutive tankmates.

The least pencilfish, Nannostomus minimus, is a tiny lebiasinid from the Potaro and Mazaruni systems of the Essequibo basin in Guyana. The second-smallest member of the genus after N. anduzei, it is poorly known in the hobby and has been exported under the name N. marilynae. In the Mazaruni it occurs with N. espei in sluggish blackwater habitats but tends to keep to marginal zones with abundant cover.