To classify a fish as a fish, fish live in water. Fish have backbones, they are vertebrates. Fish breathe using their gills. They absorb oxygen through the gills. Almost all fish are cold-blooded, and some fish have scales.
Fish that live in clear and sunny coral reefs are noticeably different from those that live in muddy rivers. Reef fishes are more likely to be brightly-colored, while those that live in murky water are mud-colored. Fish that come out at night are different from those that come out during the day. Fish that live in the open blue water tend to be dark on their backs and silvery on their sides. Only a few number of fish can tolerate both salt and fresh water.
The Class Chondrichthyes has an set order, family, and common names. The Orders are Hexachiformes, Squaliformes, Pristiophorformes, Heterodontiformes, Ocrectolobiformes, Lamniformes, Carcharhiniformes, Squatiniformes, etc. The Family's are Chlamydoselachidae, Echinorhinidae, Pristiophoridae, Heterodontidae, Parascylliidae, Odontaspididae, Proscylliidae, Squatinidae, etc. The Common Names are Frill Shark, Sixgill and Sevengill sharks, Bramble sharks, Dogfish sharks, Rough sharks, Saw sharks, Horn sharks, Bullhead sharks,Collared Carpet sharks, Blind sharks, etc.
The Family Brachaeluridae, also known as Blind sharks. Characteristics of the family is that they have small transverse mouth in front of their eyes, large spiracles behind the eyes, two spineless dorsal fins. These fish live in the West South Pacific, in shore coral reefs, and Rocky shorelines. They feed off of small fish, cuttlefish, crustaceans, and sea anemones.
The Genus and species I choose was a Ginglymostoma cirratum. The Ginglymostoma cirratum is also known as an Nurse Shark, they grow to be about 9 feet long. Their mouth is near the tip of snout with visible nasal barbels on each side. They are dark brown to yellow above, lighter on the underside with yellowish hue color, and juveniles often have black spots on it. Also they have very small eyes, and they live in or close to coral reefs.
www.science.fau.edu/.../brachaeluridae.ppt (came off a powerpoint)