This is my parents' favourite shop in Edinburgh :P
Maoshan - ms. nutritionist says you should at least eat fishes twice a week ;)
They have an overwhelming variety of seafood - mussels, exotic live big lobsters in the tank, crab, cod, salmon, scallops, haddocks, tuna, swordfishes, yellow trevally... all looking very very fresh and cut to size. Some people complain about the staff's influent English, but no worries for us, and in the end they are just really friendly and wonderful and typical HK people lol.
I especially love their adorable website. One page has a picture that says "What a variety.. can you name them? Come and visit... Bring the kids!" Don't you think it's sweet? One more word on their website, it has no opening hours and map... but it's so sweet and adorable, their not-the-best English + cute captions + pictures and even a page on their employees, totally show their genuineness!