Why does fish smell so bad

Index Newest Popular Best. New Player Log In. Newest Questions Post a Question Search All Questions Please cite any factual claims with citation links or references from authoritative sources. Editors continuously recheck submissions and claims. Archived Questions Goto Qn. Why does fish stink so bad after it has been cooked and what is the best way to get rid of that stinky smell?

Currently voted the best answer. Generally, the deterioration of fresh fish is characterised by an initial loss of the fresh flavour, which is species-specific but may in general be described as "sweet" and "seaweedy". However, the compound trimethylamine TMA is an important component of the typical fishy smell of marine fish that has been stored for some time.

TMA is a product of bacterial metabolism of the compound trimethylamine oxide TMAO , which occurs in appreciable amounts in marine fish as part of their osmoregulatory system. More specifically, TMAO may help to prevent the fish from becoming dehydrated in a salty environment. Freshwater fish generally do not accumulate TMAO because their environment is less salty than their cells. As a result their flesh tends to be milder, and they do not get as "fishy" as ocean fish.

However, freshwater fish sometimes suffer from an unpleasant "muddy" aroma. This often occurs in bottom-feeders such as catfish, and is caused by two compounds produced by blue-green algae, geosmin and methylisoborneol. These chemicals concentrate in the skin and dark muscle tissue of the fish. Acidic conditions will cause these compounds to break down, so there is good reason for the inclusion of acidic ingredients in traditional recipes.

Both do not acquire their powerful odors until humans have intervened and prepared them for consumption. All of this is explained in greater detail in the recently published, very technical book from Cook's Illustrated, Cook's Science , so if you want to get down to the nitty gritty of the acids and bacteria in play that cause the odiferous reaction, check it out.

What's more important, however, is that although fish and shellfish that's been sitting around for a little while may not be the most pleasingly fragrant, that doesn't necessarily mean it's gone bad. To determine if fish is still good to eat, trust your senses—there's a difference between a slight fishy smell and an acrid fish-gone-bad smell. Have you ever wondered why fish stink so much more than meat? Become an Indiana Public Media supporter. Learn More ». Tweets by wfiu.