Best place to buy fresh fish / shellfish / seafood?

I'm new, so please excuse what is going to be a very ignorant question ... but where is a good place to buy fresh fish and other seafood? I'm in the north and have seen the fresh fish for sale in Grand Baie on the beach, but unfortunately I'm often working during the hours they set up there. The main supermarkets don't seem to have a very inspiring range of fish or other seafood. Are there such things as 'fish mongers' or fish shops? In the north?

Any guidance most appreciated.

Check our Amigo in Pettit Raffray

Don't know what time you go to work, but the fishermen are coming back around 6,30am and are often selling in Trou aux Biches near Triolet Lane.  We get our yellowfin tuna from one of the fishermen and it's good quality, fresh and inexpensive compared to places like Amigos. And they can gut it for you!  There's also a fish shop in Triolet, it's got pics of fish in the window.