All freshwater fish have delicate flesh that begins to deteriorate before the fish dies, if it's roughly handled or excessively stressed. Keeping fish lively as long as possible in a good livewell or in a keep sack before cleaning them is one step to fine-tasting fish. Stringers stress fish more than other methods, unless the water's cold. When the water's warm, it's usually best to dispatch fish immediately and surround them with ice.
After death, fish flesh deteriorates quickly if the fish isn't handled correctly. Once they die, gut them immediately when possible to do so. Don't let sour, bacteria-filled stomach and intestinal juices touch the flesh for long. Gutting fish also bleeds them: blood left in flesh speeds deterioration. Wash gutted fish in cold water to remove bacteria, then surround the fish with crushed ice to retard any bacterial growth.
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