1 way is the easiest
The smell of stale fish product is best defined when cooking in a sealed container for a piece of test. Also the smell of spoiled fish can detect this: stick heated in boiling water knife in the thickness of the fish meat and bring it to his nose. If you want to check the quality of the smoked or salted fish, then use a wooden hairpin also pierce the fish, turn several times the pin in the thickness of the meat and bring to the nose. Benign salted fish has a normal smell in all parts of the body. When buying fish in a barrel, pay attention to the brine, it should not be perishable odor.

And yet it is not necessary to trust only the sense of smell, you also need to examine the appearance of the product.
Method 2 – Accurate inspection
Pay attention to the skin and scales of fish. Live fish should be well-fed, healthy and mobile. This fish has nezastroennoe back, the gills should rise and fall evenly, fish scales intact and must not have any stain or damage. Float fish in deep water, not on its surface. Chilled fish must be subjected to more thorough examination, since it spoiled quickly, and if not careful storage quickly becomes unuseable. Chilled fish has a thick body, put it on the hand, she in no case should not bend. Look at the gills they should be bright red in color. You can also throw fish into the water, fresh fish will quickly sink. Frozen fish should not have stains and damage, leather should fit snugly to the skin. Tap on it: if the fish emits a sonorous sound, it is good frozen product. Must not have a musty smell and mold-cured and dried fish.
3 way – the Most obvious
Tap your finger on a fish, the hole needs to quickly and fully recover. If the indentation from your finger remains, it means that the product is old and hardly fresh.