something I've never found here is a good quality fish mix, to make a sauce and make pasta with it. It is very common in Italy and easy to find fresh or frozen.
Here it's easy to find salmon and prawns. But I'm looking for something else: usually with squid, calamari, shrimp, mussels, clams and mixed shellfish.
I would have a look at the Aligro store as well (it is mainly for a professional clientele but you can get a free card to shop there via their website ). They have a very large and varied frozen food section.
This is the type of packaging we prefer to buy (photos in post #10). We often have several different packages in the freezer and take out small amounts of each item as needed.
We've found that most of the frozen mixes are not that great, probably because different seafoods require different cooking times. Invariably some bits are overdone and some under.
Of course we buy fresh whenever possible, even if the fishmonger replies with "You want 6 mussels and nothing else??"