To dissect a fish, one needs a chopping board, sharp knife or scalpel, tweezers, and scissors. The process involves examining the fish's external structure, making an incision from anus to neck to expose the internal organs, and then locating and examining the heart, liver, stomach, intestines, eggs, and bladder, as well as carefully dissecting the eye to find the lens and examining the mouth and gills. Dissecting fish provides children an engaging hands-on way to learn about anatomy and biological structures.