Depends on the fish too. Some species will keep better than others. Silvers are about the worst. In the summer, I usually gut and ice silver carp as soon as they come in the boat. Bigheads are better, and buffs don't seem to spoil nearly as fast as either of them. Common carp lasts pretty good too. There are published scientific articles on the rate of spoiling of different species (for use by the seafood industry) and silver carp about tops the list of fast-spoilers.