World's smallest fish? - Page 1
The first fish to make our smallest fish species list is the Least Killifish
. This little guy grows to about 20mm (0.8 inches) long and it is one of the species of fish on our list that is commonly kept in aquariums. The scientific name of the least killifish is Heterandria formosa
. It is a freshwater fish that is native to the United States.