Least Killifish (Heterandria formosa)

Remarks: The Least Killifish (Heterandria formosa) is the smallest live-bearing fish species in the world and is also native to the United States. While their common name calls them a killifish, these fish are not actually killifish and belong to the family Poeciliidae which includes other live-bearers such as guppies. They are a shoaling fish so should be kept in groups of 3 or more. Least killifish inhabit shallow, heavily vegetated areas of still or sluggish waters so lots of plants and little to no current are needed. They have been recorded living in brackish conditions but thrive best in freshwater. Females are much larger than males have rounded bellies. In fact, it is rare for males to exceed 0.5" in length. Due to their small size and peaceful disposition, it is important to not house these fish with large, aggressive species. Scientific Name: Heterandria formosa Common Name: Least Killifish Max Size: 1-1.5" pH: 7.0-8.0 Hardness: Soft or hard  Temperature: 64-82F Aggressivenes