https://ffxiclopedia.fandom.com has a ton of info about each fish/zone/etc., including recommended bait/rod/zones for many of the more common targets.
http://great-blue.jp/?lng=en is a goldmine of info, too. While much of the data there is dated, it's very much in-line with what you'll find on Nas.
I also recommend checking out some of the awesome guides you can find here on the forums and the wiki:
viewtopic.php?f=20&t=6476 (mainly if you're Windurstian)
http://nasomi.com/wiki/index.php?title= ... e_by_Meeep (this was the one I followed most closely while leveling, but it's worth reading Nightcoder's newer one, too)
http://nasomi.com/wiki/index.php?title= ... Nightcoder (this is probably the most detailed one that accounts for somewhat-recent changes to fish NPC prices, etc.)
Probably a few more in the Wiki worth checking out, but those should all be a good start.