Hello to anyone reading this. I made a post about this a long time ago, but with zero-cost fishing being one of the member benefits rotating through this month, I figured I would post again and hopefully at least some people find this useful. What follows is mostly copy-pasted from my old post. Happy fishing!
Cherry Tomatoes are a craftable mega snack that give 15 power, 14 intellect, and 11 strength, for a total of 40 experience. Not the best of the best, but definitely up there in terms of efficiency. The recipe for the snack is sold by one of the shopkeepers in the pet pavilion. The Bubba fish used in the recipe is an epic fish found in the Shoshun Village, so it is very rare. However, if you have the "Summon Fish" spell, you can just reset until you get one. It is the only balance fish in the pond.
For the most efficient way to fish, train the spells "Reveal Fish School," "Winnow Balance Fish," and "Summon Fish." Summon Fish requires Fishing Level 6 and can be bought in Northguard. Winnow Balance Fish can be bought from a ghost in the Labyrinth in Dragonspyre. Go to the middle top pond next to the waterwheel in Shoshun Village. Casting spells from here will take less time. First cast Summon Fish. Second, cast Winnow Balance Fish. Finally, cast Reveal Fish School. If there are no Bubba Fish (and often there aren't any, it takes luck), then the message "No Fish Affected!" will appear. If that happens, just repeat the spells from the beginning. However, if no message appears, it means there is a Bubba Fish in the lower pond. Go and catch it with a Rank 2 Balance lure (bought in Northguard). Don't worry about standing in the middle of the upper pond when casting, as no Bubba Fish will spawn there.
All credit for this method goes to Mitchell Moonsong, who coincidentally read my original post and met me while fishing. He taught me.