How to choose fish:
When we buy fish, we should first choose the fish that is alive and kicking, because if the fish is alive and kicking, it means that the fish is healthy, and when we buy fish, we should try to choose the fish with intact scales and no flaws, because this kind of fish is relatively fresh. Also pay attention to the gills. If the gills are bright red, it means that the fish is fresh and does not lack oxygen. If the gills are dark red, it means that the fish is somewhat anoxic and not very fresh. After a fish dies, the color of its gills will turn white.
Try to choose live fish. If we find worms on fish or other places when we buy live fish, we'd better not buy this kind of fish, because it may have parasites such as schistosomiasis. If we don't cook the fish for enough time or cook it well, we may get schistosomiasis or other diseases after eating it. Try to choose fish with bright colors, because such fish has better water quality, less pollution and less substances harmful to our health, so we feel more at ease when eating.
If we don't have live fish when buying fish, we can choose fresh fish from some dead fish. First of all, we should smell the fish with our noses. If it is a fish that has been dead for a long time, especially in summer, it will give off a very unpleasant smell. We'd better not buy such fish, because it may have been infected with spoilage bacteria.
When we buy dead fish, we should try to buy some fresh fish. We can press the fish's body parts with our fingers. If the fish is hard, it means that the fish has just died. If the fish has been dead for too long, we can still see the separation of the fish and the fishbone. We'd better not buy such fish, or it will affect our health after use.