Some swear by vacuum seal, I have done both over the years and have found vacuum seal is only good for 2-4 months in the freezer. Still use quality " freezer bags" cover the fillets in water, squeeze all the air out, then double bag in case of a leak. Had fillets in this for well over a year and no freezer burn and tastes just like they are fresh !! Will never go back to a vacuum sealer for my fish fillets.
Matter of fact, mine is still sitting in the original box with boxes of extra bags, hasn't been used in over 5 years. Nothing like freezing in water for perch and walleye !!