Goldfish Kingdom Aquarium Setup | Oranda and Ranchu Goldfish tank with Green Grass Background

Oranda and Ranchu goldfish tank setup

True Pets Aqua

The goldfish (Carassius auratus) is a freshwater fish in the family Cyprinidae of order Cypriniformes. It is commonly kept as a pet in indoor aquariums

Size
When kept in small indoor aquariums, goldfish tend to stay about 1 inch (2.5 cm) to 2 inches (5.1 cm) long. Goldfish may grow larger if moved to bigger fish tanks, but they usually do not grow longer than 6 inches (15 cm). In outdoor ponds, and in the wild, goldfish can grow to about 14 inches (36 cm).

Goldfish can only grow to sexual maturity with enough water and the right nutrition. Most goldfish breed in captivity, particularly in pond settings. Breeding usually happens after a significant temperature change, often in spring. Males chase gravid female goldfish (females carrying eggs), and prompt them to release their eggs by bumping and nudging them.
Source-wikipedia