I believe in the Labyrinth. Go inside the dungeon, pull up your map, and go to the fishing spell icon thing (Timor Flamecaster). There are 7 of them, 1000 gold each, and you have to be level 3. Find more info at www.wizard101central.com/wiki/NPC:Timor_Flamecaster#axzz3qSH3lnv0
So, I have heard there is a spell you can cast to scare away fish of every school, except the school you desire. Where would such a spell be located?
Mythali is correct... the spell vendor is in the Labyrinth. The good news is you don't have to fight anyone to reach him. He's standing down by the lava lake next to the quest-giver for the area. (While you're there, take some time to catch the fish that are exclusive to this area)