Fish eat and defecate through the same tube. We consider the mouth to be the entrance to the tube and the anus (Cloaca or Rectum) to be the exit – food items come in and feces go out.

In between the entrance at the mouth, and the exit at the Rectum, we will find various other anatomy to help fish digest food. Let’s learn about the Pharynx, Oesophagus, Gizzard (in some fish,) Stomach, and Intestines.

Eating, or the breaking down of food is called catabolism, the building up of new material is called anabolism and these two together make up the whole of metabolism.