1. There are about 32,000 species of fish that have been discovered in the world, and saltwater fish account for about two-thirds of them, with at least 21,000 species or more.

2. Among them, some are relatively large, such as the great white shark, megalodon, whale shark and other sharks.

3. There are also some medium-sized, such as tuna, sailfish, swordfish, salmon, and so on.

4. There are also some that are smaller in size, such as the little bee fish, clown fish, blue devil fish, shooting fish, lionfish, and so on.