Classification

• Kingdom: Animalia

• Phylum: Chordata

• Class: Actinopterygii

• Order: Cyprinodontiformes

• Family: Poeciliidae

• Genus: Heterandria

• Species: Heterandria formosa

Common Names

• Least Killifish

• Dwarf Livebearer

Identification

• Appearance: Small and slender-bodied fish with a slightly flattened side-to-side body.

• Size: One of the smallest vertebrates; males grow to about 2.5 cm (1 inch) long, while females can reach up to 3.5 cm (1.4 inches).

• Color: Generally olive or brownish with a series of dark spots or a stripe along the sides; males are smaller and less colorful than females.

Habitat

• Distribution: Found throughout coastal plains from South Carolina to Louisiana, USA.

• Natural Habitat: Prefers shallow, slow-moving waters rich in vegetation such as swamps, marshes, ditches, and ponds.

Ecological Role

• Diet: Omnivorous; feeds on small invertebrates, algae, and detritus.

• Predators: Due to their small size, they are preyed upon by a variety of larger fish, birds, and amphibians.

Behavior

• Reproduction: Viviparous (live-bearing), with females capable of storing sperm and producing several broods from a single mating. Gestation lasts about 28 days, producing 1 to 20 young per brood, which are relatively large in proportion to the mother's size.

• Social Behavior: Often found in schools among dense vegetation which offers protection from predators.

Conservation

• Status: Not currently considered endangered but could be impacted by habitat destruction and water pollution.

• Conservation Issues: Maintaining clean, vegetated freshwater systems is crucial for their survival.

Research

• Ongoing studies might focus on their reproductive biology, population dynamics, and ecological impact in their native habitats, as well as their resilience to environmental changes.