I don't speak Japanese, so all of my info was coming from a (probably badly translated) google translate copy/paste :( I do remember something about FFXI being in there now that you mention it, so maybe I'm completely wrong.. I'm fairly certain he was complaining about the weather chain and how much of a pain it would be to get that tracked properly.

The problem with the one weather domination, is that some of the fish are like..they have multiple combinations. Take these two fish for example, Wootz Knifefish Zenith and Endoceras. Going from the comments, the Wootz Knifefish is Fair -> Fog, or Clear -> Fog. That's not too hard to figure out, some kind of clear/sunny skies leading into fog. But.. Endoceras... Going from the comments is scary looking.

Endoceras: Clear -> Wind. Or Clear -> Fog. Or Clear -> Overcast. Or Fair -> Wind. OR Fair -> Overcast..

Basically, any Clear or Fair leading into Fog, Overcast, or Wind will unlock the fish. That's 10 different combinations of weather.. The fishing hole is subject to 6 different weather types (Clear, Fair, Overcast, Wind, Fog, Gales). There are no comments about Clear/Fair -> Gales, but I'd assume that's the case too. 0.6% of all the reported fish catchings appear to have that combination.

If you can write a program to narrow that down accurately, and work for every other fish in the game at the same time, please do so and share it with the community. That's far beyond me. Especially if you consider that SE might expand the weather requirements, and make something like: Clear -> Wind -> Gales. THREE specific weathers in a row. Or something more insane. Tracking that and figuring it out exactly would be.... scary.

With all of that going on, how to you prevent the program from showing false positives?