What gagoid food fish has a long body large head and two dorsal fins?

The fish you are describing is likely the "barramundi," also known as Lates calcarifer. It is characterized by its elongated body, large head, and two dorsal fins. Barramundi are popular in both recreational and commercial fishing, known for their delicious taste and significant size. They are commonly found in coastal and freshwater habitats throughout the Indo-Pacific region.