^I did several shots for this shop. The composition of this shot ticks because, to me, the lines of fish are eye-catching and the two people just rightly balance the "weight" of the boxes of the goods sold.
If you wonder why selling the fish necessitates hooking them up (animal abuse?), it's because you don't know about the delicacy among people in Southern China including Hong Kong.
These are salted fish made with several kinds of fish, the best being the King Salmon. They are not expensive in absolute term but are costly. Sheung Wan and Tai O are two of the local places famous for selling salted fish. If you have no wish to buy any but fancy a taste, try the Baked Eggplant and Salted Fish Casserole* which is served in most Chinese restaurants and fast food shops in Hong Kong.
However tasty salted fish it may be, the food is cancerogenic if consumed too much.
This is the fish story, which is not a fish story.
*The Chinese name is 魚香茄子煲