Using a fish-eye lens would be too obvious?
I had to google aquatics and came up with swimgear or fishtank stuff?
Either way, my bet would be using a wide-angle lens to show that they have lots of supply. You know, the type of pictures they sometimes use to make a house look bigger when selling it. When Looking on the internet to decide to drop by will only be encouraged by showing that the trip to the store will be worth it.