I don’t know if you’ve played monster hunter world, but I imagine this is why they made fish and aquatic bosses scarce and weak. Also, if you haven’t, monster hunter content would be very welcomed in the future
From what I’ve heard, and experienced though that might be a placebo effect, the whole black white/yin yang stuff is a secret damage modifier. White enemies take more damage while you’re standing in black and the opposite is true. If you’re hit with a debuff that “paints” you in either black or white, you also suffer this now. Taking extra damage from the color you are not. But don’t quote me on this. This boss ain’t worth the time spent trying to determine the truth.