What are the difference between cartilage and bony fish?

Technically, the most obvious disparity between bony vs cartilaginous fish comes from the fact that the skeleton of bony fish is made of bones alone, while that of cartilaginous fish is made of cartilage. There are more than 20,000 fish species in the world

Explanation:

After an organism is buried, minerals carried by water such as silica, calcite or pyrite replace the organic material in the fossil. Some common examples are most dinosaur bones, petrified wood, and many trilobite fossils.