[1] This species is the only known member of the genus Cyanogaster and its scientific name translates as the blue-bellied night wanderer, referring to its unique appearance and nocturnal habits.

[2] It was first described in 2013, having been discovered in October 2011 on a scientific expedition organised by the University of São Paulo, Brazil.

[3] When alive, Cyanogaster noctivaga is a transparent fish with a blue belly and reddish gill covers, but it quickly loses its bright colours after death.

Its eyes are large, and the shape of its snout and its dentition differs from other characins, marking it out as a new genus.

It was found in an acidic backwater, a similar habitat to that of the smallest known species of fish, Paedocypris progenetica, which occurs in peaty forest swamps and blackwater streams in Asia.