hey all, New here.. Thought i would share My results on catching the Illusive dark herring in 1hr.
If this has been covered, then i apologise.
I fished at Cauldrous Isle, Just north of utgarde keep in HF. the re spawn rates are quite fast if you keep moving around the edge of the island. Fished Fangtooth herring schools in a clockwise route around the island, if nobody else is there you will get constant re spawns. at lvl 450 fishing i didn't even need to use Lures.
After 1hour i had
107 fangtooth herring
22 bonescale snapper
11 Crystalized water
8 reinforced Crates
7 pygmy sucker
7 Glacial Salmon
& 1 Dark Herring
Hope that helps anyone who still needs the Achieve.