Been running a experiment on freezing fish.
Used to I'd fillet em, rinse rinse rinse then put them in a bag of clean water, close, and freeze. Noticed mushy crappie way to often. Lately I've been filleting them and as I do I put the fillet in a bowl of ice water, not rinsing at all, when I'm done cleaning they go straight to a zip lock bag filled with water to freeze. Firmer fillet. When I'm ready to cook I thaw then rinse.
Maybe rinsing them and trying to "clean" it up too much was putting too much water or removing too much protection from cell damage from the freezing process... :???