Killed him once, then he respawned very fast. But after that for hours nothing. Killed a bunch of 30 sharks and he was after that there. It seems all water life has a chance for spawning him.
zone into OoT from BB so you begin on Sister Isle. Then run to the NE side and go straight into the water, with clip plane maxed out you will have all the visibility you need to spot the little guy. There is no need to try to swim up to him, just dagger throw (exuberant daggerthrow ftw) and it should be enough to one shot him.
Note: you CAN land assassinate on this fish. I did so with the dagger throw.
OK I GOT LUCKY...within 15 minutes of searching this conitent...i went to sister isle auto swimming. he was on the beach when I alt-tabbed back into game. He wasnt moving fast at all. Have 200 swimming AT LEAST. I hope you get lucky as I did.
just take a boat from Freeport, and stay in the boat. while keep on tracking, drop off the boat when you have it in the track. it fly over the water, close to SoW speed. so, make sure you have leviate or SOE to chase it. Drop item you need everytime you find it
I found him this weekend pathing west on the southern boat route. He was skimming the SURFACE of the water very fast, at about run speed 2 I would imagine. Ocassionally, he would despawn (bug?) and reappear to the east. Even with a ranger tracking, he was very confusing. It was definately daytime in game when I finally caught up to him.
BTW, I camped east of the Aviak island for 5 hours previous to that and never saw him. He may not respawn there unless killed.
On a side note.. you may be in this zone a while. Although it is fun raising the swimming skill, make certain you keep tabs on your food supply. I ran out of food twice while in zone (halflings are hungry). If you are out of food when you loot the giant catfish, you WILL eat it. Thought I'd toss out that warning.
After many days and hours of checking east of Aviak Island locations mentioned below, I never saw him. I believe those are its spawn locations if someone had killed it recently. Since I was always the only one it the zone, that would be unlikely.
This morning I switched tactics, Using the map from the other post. I swam back and forth along the southern boat route. Found him within an hour right at the sea surface. I pulled him with an arrow then meleed him down. He swims fast so don't let him get away.
I clicked to loot and got the loot window. But I couldn't get the loot at first. The problem was that I was at the surface and the corpse had sunk to the bottom. I had to close that loot window and swim down to the corpse and re-loot. Finally got the Giant Catfish for the Epic prequest, TADAA
he paths around the whole sea now, but he has a couple spots he stays stationary at for a couple minutes. i marked his pathing on my map and loaded it to the map page on my sig, and here is a screenshot of his pathing
I found it around that area he seems to follow a pattern. Also it does not have the name " a flighty catfish " above it. It is just a small fish at the bottom of the ocean. I had a ranger friend help me or I would have never found it.