Mahi Mahi

I’m a fairly new player - started in March. So far my favorite thing has been filling the museum. I’ve done pretty well with some of the tips and tricks posted here and elsewhere. Have some pretty rare fish (like the golden trout!). However, the Mahi Mahi has proved so elusive.

At this point I’ve probably gone through 500+ fish bait on mystery islands throwing off the pier. Have had several giant trevally. Last month, it managed to snag multiple tuna and a marlin using this method after only 50 or so bait.

Is this just horrible RNG? Am I missing something?