I understand, thank you. Although, if the mods posted these HP values, it means they could post fishes percentage on every pond, rivers and oceans, it would be really cool if they did so.
I bet a big amount of users are currently wondering how many chances they have of getting; by exemple, an Overgrown Divider in Forgotten Lake (tested it myself for an answer of about 7%) and it would be very nice of them to have precise informations.
It was the devs choice to give us those health pools. Asking them for every fish's spawn chance and what not would be overbearing with the amount of work they have. Some people use tons of math to calculate bullet usage compared to monster health, but you don't need the percentages when you can simply know whether it's rare, very rare, common, etc. It's all RNG with fish anyway.
Alright, I know at this moment you're considerating me an asshole, but i've got some serious research on FF fishing made with percentage. I could really help the contribution of this wiki if I gave them to you.
I'm don't think it would be very helpful due to the fact that it is highly dependent on RNG and can be different for everyone (ex. how people consider stuff like Gorbacabbage to be super rare while others call it super common), but thanks for the offer anyway.