The Platycephalidae (Flatheads) are a fairly large family of fish of around 60 species of fish, of which only a few can be seen occasionally in Sydney.
They are often hiding in the sand so not easy to spot. Some people call them crocodile fish on account of their head shapes.
Rock Flathead (Thysanophrys Cirronasus)
Blue Spotted Flathead (Platycephalus Caeruleopunctatus)