Need to rinse fish before cooking to remove the “fishy” odors on the surface
To balance the salt in seawater, fish have amino acids like glycine (sweet) and glutamic acid (umami)
Sharks use urea instead which obviously doesn’t taste great
Because fish live in cold waters, their unsaturated fat spoils quicker when on surface. Also the bacteria that live in them are used to the cold temperature of the fridge so continue to spoil
Pg 188 of On food and Cooking