Fish scales are said to be rich in calcium, phosphorus, collagen and a host of other nutrients which help prevent osteoporosis though I have not found conclusive data backing this up.. many places use fish scales for making "fish scale jelly." which I have never tried.
not all fish scales from all fish are edible.. so please check to make sure you can eat the fish scales you choose to fry.
hope you enjoy My fried fish scales!