Seven years ago my daughter brought home gold fish she won at a fair. 😞 I got them a big tank and tried to give them a decent life. When I went to feed them, before I even sprinkled the food into the tank, they would swim to the surface excitedly. I realized that they were intelligent and sentient and I couldn’t keep them in a tank. So I found a woman with a goldfish pond and rehomed them to the pond. And stopped eating fish. (I had been a pescatarian and I became vegan.)
I have been scuba diving the last few days, and I remarked yesterday after a dive that I have always wondered how a pair of fish stick together as they swim quickly along the reef, not to mention the schools of fish swimming together. From a PopSci article FishFeel posted, I now understand fish have a “lateral line system” that gives them the perception to be able to do this. When diving, I can look at a particular fish and he or she will look back at me and watch me, quite aware I am there. Fish are beautiful and sentient, and they deserve to swim free.