I usually add some water to the bag, helps to submerge the bag and preserves the fish, the fish steak is 70%-80% water any ways, a little bit of water can't hurt as long as it freezes quick.. getting all the air out is the key.. Works great for prawn tails! several hand full of prawn tails in a zip lock, add some water, zip under water and freeze flat and you can stack them up, saves lots of freezer space and lasts for years.... zero freezer burn.. frozen in water with no air! last longer than just vacuumed packed I find... If you have it in your freezer for a longer time I found vacuumed packed items gets tossed around in your freezer and is prone to punctures, as soon as air gets in, your done,, freezer burn, I lost several packs cause of vacuum packing... zip lock bags in water with no air in is pretty damn good..