What is a good substitute for Barramundi fish?
Barramundi is an Asian fish also commonly eaten in Australia deep fried in dishes like fish and chips. It is very similar not only in shape but also in consistency and taste to perch.

Any type of perch like Egyptian Nile Perch which can be easily found in most markets (depending on your location) is a good substitute.

Grouper can also make a good substitute although it has slightly higher fat content and may be a bit more expensive fish.

Most Sea Bass being the same family and providing similar firmness can probably constitute a good alternative too.