Oriental Flying gurnard [Dactyloptena orientalis]

The oriental flying gurnard, Dactyloptena orientalis, is a flying gurnard of the family Dactylopteridae. This flying gurnard inhabits the Indo-Pacific Oceans at depths to 100 metres (330 ft). Their name is derived from the French word ‘gurnard’ meaning to grunt, for the grunting sound this fish makes.

The oriental flying gurnard is up to 40 centimetres (16 in) in length and is usually a grayish brown color with dark markings. The fish has huge, round pectoral finshaving many dark markings and a bright blue edge. The pectoral fins are normally held against the body, but when threatened the fins are expanded to scare predators which include sea breams and mackerel. The flying gurnard uses its pelvic fins to walk along the bottom of the ocean. The oriental flying gurnard feed on bony fish, bivalves, and crustaceans.

 Pictures: Sulawesi, Indonesia by Sami Salmenkivi

Stonefish [Synanceia horrida]

Synanceia verrucosa is a fish species known as the reef stonefish or simply stonefish. It is a carnivorous ray-finned fish with venomous spines. It lives on reef bottoms camouflaged as a rock. It is the most venomous known fish in the world. It can be lethal to humans. ^{This stonefish lives primarily above the Tropic of Capricorn. It is the most widespread species in the stonefish family, and is known from shallow tropical marine waters in the Pacific and Indian Oceans from the Red Sea to the Great Barrier Reef.}

This stonefish is usually brown or gray, and it may have areas of yellow, orange or red. This species reaches 30 to 40 centimeters long; a specimen of 51 centimeters has been recorded. This fish lives in coral reefs. It may settle on and around rocks and plants, or rest on the seabed. It eats mostly small fish, shrimp and other crustaceans.

 Pictures: Great Barrier Reef, Australia by Sami Salmenkivi

Devil Stinger [Inimicus didactylus]

Inimicus didactylus, also known as Demon Stinger or Devil Stinger, is a member of the Inimicus genus of venomous fishes, closely related to the true stonefishes. It can reach a body length of 25 cm (10 in) and is irregularly surfaced with spines and a knobby appearance. The fish has venomous spines to ward off enemies. The fish are nocturnal, and often dig themselves partially into the sandy seabed during the day. The body is red or sandy yellow and well camouflaged on sandy and coral seabeds.

 Pictures: Raja Ampat, Papua, Indonesia by Sami Salmenkivi

Bearded Scorpionfish [Scorpaenopsis barbatus]

Wikipedia has no article on Scorpaenopsis barbatus. In the picture the camouflaged fish is side-ways facing left. 

Picture: Ras Abu Galoum, Dahab, Egypt by Sami Salmenkivi