Can't say as far as horde side goes, but for alliance, once you hit level 40 and have 225 fishing, the fishing trainer in ironforge will give you a quest to be able to take your fishing skill to 300. You have to go talk to a guy outside theramore on one of the islands. He then sends you out to catch 4 different fish in various zones. Desolace, Stranglethorn Vale, Swamp of Sorrows, and Feralas if I remember correctly. Turn these back in outside Theramore and you should be able to take fishing to 300. Just a word of warning however, I did the quest and somehow my skill got bugged. Am still capped at 225. Sent a petition to gm and got the standard response of "we know there is an issue with this problem for some people, but at the current time there is nothing we can do about it" Thought I got away from that mentality when I finally got wise and left EQ.