Skill cap @ 56, but you can catch them easily enough at Fishing 11 with a Halcyon Rod & a little patience and skill.
While wiki suggests Jugner with a Shrimp Lure, I've always found it better using Insect Balls in Windurst (past/present, Waters/Woods, or Walls if you want to fish 3 steps from AH). No monsters to potentially pull up, no lost lure on accidental line breaks, and you'll only be netting Moat and Gold Carp (yay money). You'll get ~3100g for Golds at nearby NPCs, ~6-7k/stack on Moats (or 12 closer to Lu Sheng + Sandy fame), and skillups roughly every other Gold Carp. Not a bad deal as far as I see it.
Additionally, if you can craft your own Insect Balls*, there's almost pure profit in it for you in terms of skilling, gil (bonus ~6k if you make extra bait!), & time not wasted running amok to and fro to sell fish & repeat.
*(Cooking 29, but mostly stable ~26 facing south. 1 stack of mats should be more than enough if near cap, otherwise 2-3's plenty.)
