sounds to me like you somewhere in between you catching the fish and putting them in the frig they had gotten a little warm that will bring the fishy flavor out in them....i purposely bring ice chest with ice and throw them in the chest soon as i take them out of the water even in the winter...guys really think soaking the fish in water and freezing the fish in the water is the best way to freeze...it is not, fish is much better frozen in plastic with all the air taken out...i use a seal a meal...but you may already know this.
sometimes crappie can get a strong flavor and that can be because of there diets, what they may be foraging on.
CJ