Neoheterandria is a genus of small livebearers in family Poeciliidae, native to Pacific-slope and Caribbean-slope river drainages in Panama and Colombia. Atlas species are diminutive, spanning roughly 1–2 in, among the smaller members of the livebearer family. Like other poeciliids, females carry developing young internally and give birth to free-swimming fry rather than laying eggs, and males fertilize females using a modified anal-fin gonopodium; the genus shares the slim, laterally compressed body typical of small forest-stream poeciliids.
The genus is more a curiosity for livebearer specialists than a mainstream aquarium fish; where kept, care generally follows small-poeciliid practice - warm, well-planted tanks, fine live or small prepared foods, and gentle tankmates given their diminutive size. Conservation data are limited - two of the three atlas species carry a Data Deficient assessment and the third is Least Concern, reflecting how little survey work has reached these small-range Central American streams rather than any documented decline.