Least Killifish (Heterandria formosa)
Fish in the family Poeciliidae. Easy care. Freshwater.
Quick facts
Scientific nameHeterandria formosa
FamilyPoeciliidae
Also known asDwarf Livebearer, Least Livebearer, Mosquitofish (dwarf)
Care levelEasy
Reef safetyFreshwater
TemperamentPeaceful
DietOmnivore
Adult size1.4 in
Minimum tank size5 gallons
Water parametersTemp 66-80°F, pH 7.0-8.0, GH 8-25 dGH
Appearance
Diminutive livebearer with a dark lateral stripe and a spot on the dorsal fin; females have a dark anal-region marking. Despite the name, a true poeciliid, not a killifish.
Difficulty and care for the Least Killifish
Easy
Origin and habitat
Southeastern United States
Keeper notes
Extremely peaceful and tiny; one of the smallest fish in the world and safe even with dwarf shrimp. Easily outcompeted, so keep with calm tankmates.
Log Least Killifish in your reef tank
Reef Trak gives you the full record on every species in your tank: acquisition date, source, photos, parameters at time of stocking, and links to maintenance and feeding events. Track Least Killifish alongside everything else in your reef.
