Abstract The purpose of the experiment was to show the influence of water temperature in a goldfish. The hypothesis “Increase in temperature, will increase breathing rate”, that was tested states the effects of water temperature and breathing rate inevitable to occur in a goldfish. The major findings proved the hypothesis to be true. Findings such as, when warm water was added the goldfish respiration would increase. However, when the temperature dropped the respiration decreased. The evidence found in the experiment proves the hypothesis to be true and accurate. Introduction Goldfish are ectoderms meaning that it absorbs heat from its surroundings; the majorities of these ectoderms are cold-blooded and include reptiles, fish, and amphibians (Spaccarotella, 2015). On the contrary, endoderms generate body heat from metabolism, mammals like birds are consider to be this because they are cold-blooded (Spaccarotella, 2015). According to the Michigan Government (), “the metabolic rate of fish and aquatic organisms also increases with increasing water temperature, and additional oxygen is required for respiration”. Therefore, as the water temperature increases additional oxygen is required. The hypothesis that was tested states whether the water temperature influence the respiration in a goldfish. It is predicted that the goldfish breathing rate would slow down if they are exposed to cold water. Materials and Methods The goldfish experiment was performed according to the lab manual provided in class (Spaccarotella and Rongsun Pu, 2015). The control goldfish was never exposed to the conditions of the experimental fish. The control fish room temperature was (22 Degree Celsius). There were six control variables for the experimental and control group. The first variable of the experimental and control group was the kind of fish to be studied, both groups used a goldfish. In addition, the control and experimental group both had