There are about 40 living (extant) species in this order, grouped into four families.

Most Gonorhynchiformes live in marine (saltwater) environments, often near the ocean floor. Some species prefer shallow coastal waters, while others live in deeper areas. A few species can also be found in freshwater.

These fish typically have long, slender bodies, small mouths, and no teeth. Their scales are smooth and shiny, often silvery or pale.

They feed on plankton, small crustaceans, and organic material found on the seafloor.

Milkfish are an important food source in many countries. In fact, the milkfish is one of the oldest farmed fish in the world—people have been raising it for food for hundreds of years.