You mean the key to the chest with the flippers in it?
Maybe there is intent to make a new use for the fisherman's fish... maybe they used the same item profile, and you could give it to the zorbi due to overlooking some previous programming... Sorry to be a pessimist, but I didn't get a fish. Even relogged a few times to see if it didn't appear the first time. I would love to get some doubled up items to hold over my head though.. people love seeing random keys, and the matchbox from the scarf quest-line is pretty cool looking!