Longfin herrings, ilishas, pelonas and pristigasters are the common names used for the members of the Pristigasteridae family. They are moderate-sized fish, recognized by their terminal mouth, complete series of scutes along the abdomen, and long anal fin.
Longfin herrings are found in all seas from about 30°N to 30°S. They are typically marine but can also be found in brackish and freshwater. A few species in South America appear to be restricted to fresh water. Most of them inhabit shallow coastal waters and estuaries. They frequently occur in large schools. Most species feed on small planktonic animals.
There are 9 genera and about 38 species of Pristigasteridae worldwide. Malaysia has about 4 genera and about 12 species.