I don't get any fishiness. I don't really think the "Noses" that create these fragrances would have paired up something "fishy" with "florentine iris" or the like! This ambergris is the musk, or musk substitute if you will. It does smell somewhat meaty somehow, but it is clean. Aquatic smelling, but not fishy.
Our noses definitely play tricks on us...but I can't really shed anymore light on your claim. I know that ambergris is regurgitated whale vomit, which rises to the surface. The beaks of the squid that the whales eat supposedly irritate their stomachs, causing them to vomit. YUM! Let's make cologne out of it! (what the hell were they thinking?!) Well, it works for me!