This experiment was designed to identify the effect of cold-water temperatures on the respiration rate of goldfish. The respiration rates helped to identify the goldfish as being ectotherms or endotherms. Organisms exchange gases with their environment through a process called respiration or breathing. Aerobic respiration, also known as aerobic metabolism, occurs when oxygen is taken into the body and sent to all its cells; the oxygen is then used to break down food for energy (White and Campo 2008). Respiration can be experienced through several structures such as the lungs, tracheae, gills, and integument in order to obtain oxygen. All organisms that experience respiration are either endotherms or ectotherms. Ectotherms are animals that depend on their environment for body temperature. These animals respond to changes in their environment in order to maintain homeostasis, the stable, internal conditions of the organism. Animals that are warm-blooded and can regulate their body temperatures internally regardless of their environment are endotherms. For ectotherms, regulating body temperatures can require more work. Those aquatic animals have adapted several techniques to stay alive. Larry Crawshaw explains that animals, both aquatic and terrestrial, seek to avoid stressful thermal environments or to compensate for the temperature change by mostly lowering the metabolic rate (1979). Lowering the metabolic rate allows certain enzymes to be produced and chemical reactions to happen within the fish that actually warms it up. While lowering metabolic rates are important, respiration regulation is also important. Stephen C. Wood also believes that ectotherms need behavioral mechanisms for temperature control. These mechanisms could include slowing breathing rates to conserve energy and releasing certain chemicals into the body (1991). This…