what is the difference between the bony fish and the cartilage fish?this is about the fish
The bony fish, or osteichthyes, are generally considered to be the more advanced group of the two. These fish have an ossified skeleton with a calcium bone matrix. They also have gills with bony supports, gill rakers, and a gill cover known as the operculum. The ray-finned fishes, which are the largest group of bony fishes, have fins that are supported by internal bony structures.
The cartilage fish, or chondrichthyes, have a skeleton made of cartilage, which never ossifies. Their fins lack bony internal support. They have 5 to 7 gills which are connected to the outside by a series of holes called spiracles. Many species of cartilage fish must swim continually in order to keep water flowing across their gills.