It's swim bladder, also called fish belly, and it's called "marine ginseng". It used to be a tribute, of course you can eat it. Rich in phosphorus and high protein, it has the functions of tonifying kidney, replenishing essence, nourishing tendons, dredging veins, stopping bleeding, removing blood stasis and reducing swelling. It can be used for treating nocturnal emission due to kidney deficiency, postpartum wind spasm, tetanus, hematemesis, metrorrhagia, traumatic hemorrhage and hemorrhoid. In fact, even fish scales can be eaten together. When stewing fish, you can cook the swim bladder and fish scales in the soup, which will be especially delicious and nutritious.