Building block ingredients of fish food:
Amino acids are the basic components of proteins. An example of an aquatic diet that is a good source of amino acid is a crumbled hard boiled egg offered to small fry. DL-Methionine, an essential amino acid from spinach, green peas, garlic and fish meal enhances the headgrowth of Lionhead goldfish.
Fats that are broken down into fatty acids are the main source of energy in fish especially for the heart and skeletal muscles. Fats also assists in vitamin absorption. Vitamins A, D, E and K are fat-soluble or can only be digested, absorbed, and transported in conjunction with fats.
Carbohydrates are molecular substances that include sugars, starches, gums and celluloses. Most of the carbohydrates that are incorporated into aquatic diets are of plant origin and are sources of the enzyme amylase. Carbohydrates, however, are not a superior energy source for fish over protein or fat but digestible carbohydrates do spare protein for tissue building. Unlike in mammals, glycogen is not a significant storage depot of energy in fish.

We sat by the pond and dropped in anything we could think of. If the fish ate something we made a note. Then we put all the things the fish liked in a blender and voila - fish food!

Did you know humans can eat fish food too?