Sunstone Island

Sunstone Island carries the caption "It used to be a quarry, but something strange happened." It offers a crab cage and a bait crate, and its residents include Angler, Merlin, Rhea, Beachkeeper, Shipwright and a Travelling Merchant.

The wiki documents only 9 fish here, which is a compact pool: 2 Legendary, 2 Exotic, and one each of Trash, Divine Secret, Rare, Common and Relic. The small size means you will see the same species often, and the interesting part is how top-heavy the values are.

Crustal Colossus is a Divine Secret that averages C$30,003. Behind it come Speed Core (Exotic, C$10,121.20), Tartaruga (Exotic, C$6,187.50), Sunfish (Legendary, C$750) and Communication Circuit (Trash, C$310). Notice that even a Trash item like the Communication Circuit sells for more than many Common fish on other islands, and that the island's odd list also includes names like Voltfish and Wiifish.

No rods are listed as sold here, so this stop is for fishing, not for shopping.

It suits players who already have a solid rod and want a short pool with two Exotic fish that sell for thousands. If you prefer wide variety, a larger zone will give you more to catch.