It is recorded to occur along the western portion of the Sabine River basin, according to North American Native Fishes (NANFA).

[9] It has also been collected as far west as Humble, TX in small sand pit ponds after the 2017 floods associated with Hurricane Harvey.

Heterandria formosa live primarily in vegetated, slow moving or standing freshwater habitats, but this species also occurs in brackish waters.

Like most poeciliids, male anal fins are modified into a gonopodium (intromittent organ) that is used to deliver sperm and impregnate females during mating.

Other traits that displayed inbreeding depression were offspring viability and maturation time of both males and females.