A side effect of Darkmoon Faire fishing; you can get a Draconic Bottle with a random Dragonflight recipe at turn-in.
Vets with DF can fish around the isles without leveling the profession and there are DF items like coins of the isle that can drop, and The Great Swog can sell you a bag depending on the coin exchange, but getting a gold coin seems a rarer drop.
A gold coin of the isle can get one a special bag; Immaculate Sac of Swog Treasures from Great Swog that may have a blue item, but as I haven't found a gold coin so I cannot say if level locked to open for or to use the Aquatic Shades if it dropped from the bag, personally.