This experiment was conducted to investigate the following hypothesis: Cold water temperature will decrease the respiration rate of a goldfish. Fish breathe by exchanging gasses through gills that are located in the gill cavity. The fish push water across the gills to gain O2 and to dispose of CO2 (Hamilton). Each time the fish breathes, the gill cover (or operculum) moves. This shows an accurate reading of the breathing rate. Goldfish are Ectotherms, meaning that they do not have ways of maintaining a constant body temperature (Kennedy). So, if immersed in cold water, the fish’s body would cool as well. As the fish’s body cools, the chemical activity in it’s cells decreases which lowers the demand for ATP. As the demand for ATP decreases, so does the cells need for oxygen (Hamilton). This causes a decrease in the fish’s respiration rate. As the water temperature decreases, we should see a…show more content… We then placed a goldfish into the beaker and allowed it to become accustomed to the new environment. The water temperature was measured using a Celsius thermometer and then the data was recorded. Once the water temperature was recorded at 25̊ C, the operculum breathes per minute were then counted and recorded. The process of counting and recorder the breathes per minutes was repeated two more times. The experiment began by repeating the initial processes of the previously described control but instead of allowing the goldfish to remain in a stable water temperature of 25 ̊C, the water temperature was decreased slowly. The glass beaker was then placed into a larger bowl containing ice in order to record decreasing temperatures and breathes per minute. The temperature and breathe recording process was repeated three more times at different temperatures: 20 ̊C, 15 ̊C, and 10 ̊C. This experiment was performed by five groups to ensure a large sample size (Hamilton).