Bluegill

The bluegill is a river fish in the that appears in all games. It appears from 9 AM to 4 PM year-round, and it sells for 180 Bells beginning in.

Donating to the museum
Blathers will give a speech on the bluegill when it is donated to the museum:

In
Blathers gives no specific speeches once the bluegill is donated, but he posts a description for it.

In
Once donated to the museum, the bluegill can be found in the recessed tank in the main exhibit room with the black bass and koi.

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

Real-world information
Of tropical sunfish body shape, the bluegill's most notable feature is the blue or black "ear", actually an extension of the gill cover called the opercular flap. Its name, however, comes from the bright blue edging visible on its gill rakers. Also called the bream, this fish tastes nice. It is very common and often fished. Catfish, bass and turtles prey on the bluegill.