Freshwater goby

The freshwater goby (ドンコ, Donko) is a rare fish that can be caught in the river in every game. It has a small shadow, and it appears all year round. It can be caught between 4 PM and 9 AM.

In
After donation, the freshwater goby can be found in the middle-left tank.

In
An information board in the aquarium will display this description of the freshwater goby after donation:

In
Once donated to the museum, the freshwater goby can be found in the second level of the waterfall tank with the yellow perch and pale chub.

Fishing Tourney
During a Fishing Tourney, when given a freshwater goby, Chip will say the following dialogue.

Real-world information
The freshwater goby is typically a native fish to tropical and temperate areas of Asia. There are numerous types of these fish, known as haaze in Japan. All live in freshwater rivers where they scavenge the riverbed for prey.