Pretty much the "it" moneymaker in FFXI now that Blinkers got nerfed. However, you'll need at least lvl 90 fishing, an Ebisu Fishing Rod which will run you in the ballpark of 10-15 million, and Serpent Rumors KI which costs 95k GP, or about 6-8 weeks of turning in GP fish without missing a day. Lu Shangs wont cut it on these fish, they'll break it most of the time you get a line snap which is about a 1 in 3 chance. You'll also need 80-100 Minnows/Sinking Minnows or ~25 stacks of Sardine Paste/Bluetail Slices and fish for anywhere from 16-20 hours each day if you want to reach the 210 fatigue cap on them. Needless to say it's not recommended for everybody.