I bought a package of frozen, individually wrapped, vacuum-sealed pacific cod fillets (about 150-200 grams each) from what I thought was a reputable brand (and not the lowest price) in my nearest supermarket, and attempted to pan-fry it. I defrosted it by running cold water in the sink as advised in this answer (it took about 15 minutes). When I opened the package, a large amount of water had separated from the fish. I carefully dried the fillet with towel paper, coated it with flour and put it in a hot pan over maximal heat as explained in this other question. Despite my efforts and the hot pan, the fish immediately started releasing even more water, dissolving the flour and turning into a small 75-100 grams of boiled, chewy fish fillet instead of a nice fried, tender one.
So I am looking for advice on how to properly choose frozen fish in the first place. I know that it should be properly vacuum-sealed and from a reputable source (whatever that means). But even then, some frozen fishes will loose a lot of water (it was obviously the case here). What qualities should I look for when buying it? Can I tell by the fish aspect or something else if it's good or not? Are some species better than others?