If you are looking for a specific fish and what rod/bait/area for the best attempt at it then try this:
http://www.finalfishing.com/
However, if you are more interested in looking for a range of fish for you're fishing lvl, or what types of fish are in a certain area, try this one:
http://www.clanwind.com/ffxi/fishing/default.asp
I've used both of these sites for a long time, each helped me get fishing to 90 ^^, clan wind is a little outdated and doesn't have the newest fish from ToAU, however it does have a very nice counter that shows you the current moon phase and how long till the next full or new moon.