The Fishmen are a wise race of talking fish featured in The Wind Waker. There is a particular one that can be found repeatedly jumping out of the water near each of the 49 islands of the Great Sea. However, the only way you can talk to him is by purchasing some All-Purpose Bait from Beedle and tossing it on the water when he is within targeting range. He will occasionally complain about your choice of feed, but will repay you nonetheless by coming up and filling in part of your Sea Chart. He will also share with you some useful info, changing according to which island you are at.
 Fishman's Hints
Here are all of the hints that Fishman will give you near each particular island when you talk to him.
Skull Necklaces: "I hear there's a fellow on Windfall Island who's collecting Skull Necklaces. You know who it is, fry? I don't. Sorry. What I CAN tell you is that those piggish monsters you see here in the Forsaken Fortress seem to carry those Skull Necklaces around all the time. Not that I think it's easy work stealing anything from the likes of those guys."
Ice Arrows: "I hear that somewhere out in the wide world is a handy arrow that can freeze anything. With something like that, you could even freeze that nasty monster in the Forsaken Fortress... for a while anyway. But then, what would you do with a frozen monster, you say? Good question, fry. Why, I'd say that you'd give that thing a whack and watch it shatter into teeny-tiny pieces!"
Magic Armor: "The little shop master on Windfall Island apparently got his hands on a truly amazing treasure. He calls it Magic Armor or something like that. It's a pretty cool magical relic, from what I've heard. If you want him to give it to you, try staring deep into his eyes and winning him over with flattery, fry! Ahhhh ha ha ha ha ha ha ha ha!"
Iron Boots: "Are you thinking you want to get into that cave, small fry? The one that's protected by the crazy winds on that island? Heh heh heh! OK, then. Let me just tell you a little secret... if you go five squares south and one square east from here, you'll reach Ice Ring Isle, where you'll find an item that will make you as heavy as stone. If you get that item, you won't have to worry about being blown over by the winds."
The Ghost Ship: "You'd best be careful sailing these waters on nights when the moon is full. Well, if you like pure soul-freezing horror, fry, then maybe you can handle it."
Big Octos: "If you see seagulls flying around some sea waters, that's a sign that you need to be wary, fry. Because the seagulls flock to wherever Big Octos appear. I tell you! Those things don't mess around!"
Triforce Chart: "Hey small fry, do you know about the gold Triumph Forks? They're there, I tell you... on that island... the chart is there is what I mean to say. But the cliff face rises sharply, and even if you wanted to climb it, there aren't any ledges or footing you you to grab onto. So what are you going to do, small fry?"