Keeping them cold from start (catchin) to finish (freeze'n) could help . I always try to put fillets in ice water when cleaning. Then after rinsing , place in ziplock, add a little ice water , squeeze out air and most of water with out crushing fillets, then freeze as usual. I never have any complaints.
Some folks keep Crappie on ice too long or let die in livewells and they will turn mushy fast.