This mini-guide will let you avoid fishbotting a whole night just to go from level 1 to 75, but from level 1 to 450. Depending on where you chose to place your character, if it is in Azeroth, the trainers will only take you to 300 and in Outland to 375.
Place your character so that he can interact with an fishing trainer and still have his bobber land in fishable water. For example Marcia Chase in dalaran. Or Paxton Ganter (click for map).
I wouldn't recommend botting in Dalaran 'casue of the risk of getting cough is significally higher than at, for example, Paxton Ganter.
Create a macro like this:
Make sure you open the window from the fishing-trainer-npc where you can chose to train the fishing skills.Code:/click ClassTrainerTrainButton /cast fishing
Like this:
And bind your fishing-key from the bot to your macro.
If there is a higher fishing level available, it will learn it. If not: it'll continue to fish until there is=)