We did a photosynthesis/cellular respiration demo in biology. There is an indicator in the water that turns yellow when CO2 is present and blue when O2 is present. After the fish turned O2 into CO2 the water turned yellow. Then we put a plant in and put it in the sun and photosynthesis happened to turn the CO2 back into O2. The fish is still alive 😊. Also, the colors are hard to see but we could see a slight difference.
