Pop-eyed goldfish

The popeyed goldfish is a rare fish in the found in the river. It sells for 1,300 Bells in Tom Nook's Store and appears all year, during the hours of 9 AM to 4 PM. Its shadow size is tiny.

In City Folk
When accepting the fish for the Museum, Blathers will say: "Popeyed goldfish look like any other ordinary goldfish whilst still juveniles. As they begin to mature, their eyes bulge outward and gradually assume that distinctive appearance. Imagine how appalled you'd be if you brought one home thinking it was a normal goldfish...".

Encyclopedia Information
In the Fishes window in Wild World, the caption about the Popeyed Goldfish says: Though their eyes are big, their vision are poor.

Further Information
The Carassius auratus shares its scientific name with all types of Goldfish. The Popeyed Goldfish, or Black Moor Goldfish, is a harmless fish that lives in slow-flowing ponds, ditches, rivers, and lakes. It is a specially bred type of carp with large, protruding eyes, which to some peoples surprise has poor eyesight as a result of its heavy inbreeding. It is related to other types of telescope fish, Carp and is indirectly related to the Koi. It feeds off of small insects, crustaceans, and plants. In China, it is called the dragon-eye.