i have no experience with saltwater fish, but i would advise highly against releasing ANY pet into the wild. if it is not native in your area, it can become a pest, but more likely it will just die, not being used to the chemistry of the sea. can you not take it back to the store where you got it?
50gal planted - yoyo loaches, BNs, odessa barbs, giant danios
33gal planted - praecox rainbows, gold ram, bolivian rams, sparkling gouramis, licorice gouramis, lots of shrimp
2 x 5gal planted - bettas