are you refering to the "panther grouper" i have heard them being refered to as barramundi cod before in Australia (white w/black polka dots?)
if so i have kept one before - awesome fish, one of my favorite sw predators - if i set up another aggressive sw tank again it will be my first purchase again - i love their look and they are pigs come feeding time - mine grew pretty fast but i ended up getting rid of him due to disease outbreak in the tank - they lose some of their color when they get bigger but they are awesome looking when their like 6-7 in - great color and great personality