Okay, I've been spending 4 nights trying to catch this damn fish and couldn't get it.
I've done a couple of things before catching it so I don't know what is revelant in all of the following infos but I hope some of it will help you guys.
First, I tried many different nodes in the area like Cron Castle and some other that I found on forums with no success.
Here's what I did that probably (at least one of these) made it work:
---> I abandonned the quest and took it back (some guy said it could be buggued...).
---> I tried easier nodes to level up my Fishing Skill to Skilled1.
---> I went away fron Cron Castle and the quest giver area and tried fishing in the open (see my screenshots).
---> I did not check the "Throw away useless items caught during auto-fishing" box (Tongue-Soles are white quality fish!).
In a single night, i finally caught 3 Tongue-Soles (not beltfish as mentionned in the quest). Not one by pure luck but 3 of them! That means that something clearly was stopping me from fishing this fish before!
After that night of fishing my Fishing skill was at Skilled1 91%, I was using a Thick Fishing Rod and a Silver Embroidered Fisher's Clothes +1 (I ran out of Fishing Bonus food at this moment and my Bait Paste probably didnt last long enough to catch these Tongue-Soles...).
Check out my screenshots for location.
Good luck!
1
Anonymous 1-06-2016 20:00
While screenshots are beeing proceeded by moderators, here's a link to the imgur album: http://imgur.com/a/veZ0u
@Azrhael, got one about 1min around the location. thanks^^
0
Anonymous 23-06-2016 09:48
Commenting so that hopefully anyone looking to finish this quest can avoid wasting hours of their time like I just did.
This information is accurate for the NA version of Black Desert as of June 23rd, 2016.
Despite the fact that the quest tracker says that you need to give Erio a Tongue Sole, whatever that is, the fish he is looking for is, in fact, a Rock Hind, which are white-quality fish that can be frequently caught right from the island where Erio is. Hope this helps someone. Hope this saves future fishers some headaches down the line!