and monitoring the rate at which each fish opens and closes its mouth. That mouth action corresponds to its rate of respiration, which increases with stress levels. In lab tests, the AI ...

Fish often avoid intense stimuli, but scientists and animal welfare groups have long debated whether fish can feel pain. So is there an answer? Animal rights organization PETA claims on its ...

"Researchers have worked together to create a comprehensive ecosystem, where aquatic plants produce oxygen through photosynthesis to supply fish respiration, and fish excrement provides nutrients ...