If it is a Silver Toadfish here is what Hutchins and Swain Sea Fishes Of Southern Australia has to say about it.
"Silver Toadfish, This tropical species is often found in more southern waters of Australia's east and west coasts, usually in schools. Best recognised by the silvery stripe along the side, and greenish back with dark spots. A fearless predator well known for its attacks on humans. Its teeth are shaped like a parrot's beak, and can easily bite through bone. In a feeding frenzy, it is as dangerous as a shark, attacking everything in sight. Like all members of the Toadfish family its flesh is poisonous, also known as the Northwest Blowfish and Silver Pufferfish. Max length 97cm."