Oo You must have fished at the wrong place.
They don't bite well but they aren't THAT scarce, after all they are a direct catch if I am not mistaken.
I fished them up in half an hour with the Lv 51 insect lure you can buy in western coerthas at
Western coerthas; unfrozen pond.
I can recommend the site Silverbane linked. It has virtually all the information you could possibly need.
I agree though that being dependent on such a site is ludicrous game design. FF tells you waaay to little about the fish you want even after you caught it.