Unlike its brother gathering professions, fishing is significantly more complicated. There is a fishing log, but unlike the gathering log it does not give specific locations on where to find the nodes. In fact, there are no nodes at all. You just have to toss your line out there, but there are particular locations all around Eorzea that one has to discover. Unlike mining or botany (at least until level 50), there are some circumstances that effect what can be caught and when. This makes fishing kind of the biggest pain in the butt out of everything else in the game, however this is kind of a good thing. People, unless very bored, don't want to put the effort into leveling fishing, so those that do are rolling in the money at higher levels.