Sharks and fishes dont differ. Sharks are also fishes, the largest of the piscean species. If you ask about goldfish, then there are many differences, apart from the size. Goldfish and sharks have different diets. All sharks are carnivorous, however, only about 10 species are dangerous to humans. Another thing- Sharks dont survive very long in captivity, while i doubt you will ever find a goldfish in the wild. Also, Sharks can't move their gills like other fish can, so they have to constantly swim around, otherwise they will suffocate. They can also close their eyes (which they always do when biting into something). They don't have swim bladder like other fish. Their skeleton is made of cartilage instead of bone. They also have replaceable teeth, with new teeth constantly replacing old ones.
