How to identify high-quality aquatic product?

  So how we can identify the freshness of the whole fish?The eyes should be clear and bulging not cloudy,that's the most obvious and distinguishable part.gills can be red and tender pink,rather than dark or even black(indicating that myoglobin has been oxidized to denatured myoglobin),the skin of fresh fish would be as tight,clean and shiny as a live fish.But there is still one thing worth remembering,"Fresh"isn't always better.The fish labeled"fresh"may have been stored for a few days during transport,or they were not preserved or frozen in a timely manner after being caught.Sea Frozen locks in nutrients.At the same time,there is another misunderstanding:fish will deteriorate more quickly after death due to stress,and the quality is not as high as that of the frozen fish in a standardized Sea Frozen.However, for ship freezing, only BFQ can be chosen, while for land freezing, one can choose between BFQ and IFQ.The fishing methods and the ways of sea transportation and storage also have a certain impact on the quality of fish. For instance, the best quality is achieved by using light catch and freezing in insulated warehouses with water for refrigeration.For squid, a deep red tube indicates fresh quality, while a white tube indicate frozen dead squid, which is of poorer quality. Squid caught by jigging is of better quality than those caught by light catch and trawling.The degree of damage to the skin on the body can also to some extent show the freshness of the squid.