Only caught in new fishing hot spots (gulls and fish). Regular spawn of hot spot in front of Iliya Island harbour. Varies but one is NW if Ostra Island and between there and Arakil Island. Node to connect is Baremi Island.
Other spawns possible in the general area. Possibly in other areas too but this one if reliable so far.

Another spot where it has been caught in a hot spot is south of Marka Island along the Olvia Coast (and node).

Note that they can not be dried.

Also currently there appears to be a bug where the +XP yellow icon shows but it doesn't give XP or very little. Less than other similar quality fish certainly.

hotspots seas of nox, seas of olvia