When you say on the title "Salt Water Aquarium Store" first things comes to mind would be Brick and Mortar. Something I would like to pin on my locations in the case I'm around that area I could visit.
Some of these "stores" listed seem more, garage or online only stores. Maybe a change in the title?
The showcase features websites that meet the saltwater items criteria. If they have a website, and they sell saltwater related items such as fish, corals, dry goods, then they should be included, and have. It features both online and brick and mortar stores. Some places have both online and a physical, others are just online only, and others are physical only.