Anal
• Begins at anal opening and varies in extent towards caudal fin. Some cases dorsal, caudal and anal fins fuse e.g. eels. Paired pelvic and pectoral fins
• One on either side of fish. Location and size varies with species. Pectorals midway upside of body, major propulsive appendage of most reef fish.
Mouth
Vary in size, shape and orientation. The extent in which fish can extend their jaws varies with species.
Gill plates/Operculum
Covers gills, protects them from damage.
Lateral line
A sensory groove that runs along lateral surface on either side of body. Can be visually distinctive, often curved as it runs from near pectoral fins to caudal fin.
Caudal Peduncle
Narrow part between body and tail. Dorsal surface known as saddle sometimes has blotch type marking association with it.
Finlets/scutes
Found towards tail especially in fast swimming pelagic fish. Finlets look like small, stiff triangular fins on both dorsal and ventral surface. Scutes are large scales or bony plates along the body towards the caudal peduncle. Thought to assist efficiency of swimming in fast, pelagic species.