Originally described from Guyana by Günther in 1864, Moenkhausia oligolepis has a range spanning the entire Amazon and Orinoco basins and various coastal rivers of the Guianas, making it another suspiciously widespread species. Illustrated specimens are ones I've collected in various corners of the species range, shown here in a GBIF map of aggregated collection records. Another similar species, M. sanctaefilomenae, is popular in the aquarium trade where it is known as the 'redeye tetra'. That species is restricted to the Parnaiba and São Francisco drainage basins. - Nathan Lujan.
I could send you 20 or more, all different. And everyone from complete different location. This really red eye morph is one is from a few Km north of Leticia. Jacques Gery was working on these for decades. - Heiko Bleher
Jacques always said that as long as we do not find the M. sanctaefilomenae at its type locality we will never know what it really looked like. He did not believe the one in the hobby is sanctaefilomenae. I went into the area as early as in 1974, 1975, and many time the following years but every time there was less of a chance finding the species, it's all deforested, all altered because of dams, and roads, bridges, and the area had became a desert.
