Lemonfish

You catch Lemonfish at Desert Depths. It is a Common fish, so you need a rod of level 1 or higher. It is herbivorous, so only herbivorous bait catches it: Rice, Corn, Sweet Potato, Wine-Soaked Rice, Fermented Dough and Kelp. When a Common fish takes herbivorous bait here, it is Lemonfish 33% of the time.

In the Aquarium it earns 60 Gold an hour.

Dave can bring it back too, from a dive while your boat is at Desert Depths.