English: To control buoyancy the fish will “gulp” water and force it through its gills. Through this process dissolved oxygen goes into the fish’s blood stream. This oxygen then travels to the swim bladder and diffuses into the swim bladder controlling the buoyancy of the fish. To go up the fish relaxes its muscles and allows for the swim bladder to increase in size and to go down the fish will contract it’s muscles force the gases back into the bloodstream which will continue traveling throughout the body.