What is "argentiniformes"

Argentiniformes is an order of ray-finned fish whose distinctness was recognized only fairly recently. In former times, they were included in the Osmeriformes (typical smelt and allies) as suborder Argentinoidei. That term refers only to the suborder of marine smelts and barreleyes in the classification used here, with the slickheads and allies being the Alepocephaloidei. These suborders were treated as superfamilies Argentinoidea and Alepocephaloidea, respectively, when the present group was still included in the Osmeriformes.

They contain 6-7 families with almost 60 genera and at least 228 species. A common name for the group is marine smelts and allies, but this is rather misleading since the " freshwater" smelts of the Osmeridae also live predominantly in the ocean.