Red Indianfish

Found singly or in pairs, often hiding and blending in with the substrate, around coral outcrops and amongst sponges, in deeper waters of coastal and outer reefs. Recognised by the compressed body and saifin. Can be difficult to spot amongst coloured sponges, often swaying in the current resembling a leaf.
Indo-Pacific - Australia

Prowfish are a compressed fish with a tough skin (instead of scales) which they shed periodically to rid them of parasites.
They have no ventral fins, and combined with pushing with their dorsal-fin base they use their gill opening as propulsion to move around the reef.
As with all Scorpionfish they are masters of camouflage.