The goldfish (Carassius auratus) is a freshwater fish in the family Cyprinidae of order Cypriniformes. It is one of the most commonly kept aquarium fish. A relatively small member of the carp family (which also includes the Prussian carp and the crucian carp), the goldfish is native to east Asia.
Goldfish are a golden yellow or orange fish that live in fish tanks or man-made ponds as pets. They are freshwater fish, meaning they live in water that isn't salty.
The reason their eyes look bulgy is because they don't have eyelids and can't blink, but they have great eyesight and can see up to sixteen feet away.
Just like people, goldfish need oxygen to live, but they don't breathe in air using lungs, like we do. They take water in through their mouth and push it out through their gills, which are special organs with openings near their head. The oxygen they need stays in their body.
Goldfish might be a bit smarter than you think. Some goldfish can see and remember well enough to distinguish between people. They often notice the person that feeds them each day and will get excited when they see them. There have been cases where goldfish have been trained to do tricks like swim through mazes, swim through hoops, or even push a ball into a net.