The Goldfish Guide by Peggy Ferguson Goldfish, sometimes overshadowed in the pond by the bigger Koi, is every bit as beautiful and exciting to watch. They may even be just a bit hardier although they generally do not live as long as a well-kept koi. Goldfish will live 20 to 30 years while a well-kept koi will live about 50.
Comets are single-tailed goldfish and are considered the most hardy of all pond fish.
There are three common classifications of the comet, Pond Comet , Sarasa Comet and Shubunkin . When small, it may be sold as a feeder fish but a larger one will add a beautiful color to your pond. Many times a sarasa comet will have red spots on a white body. The reds on a sarasa comet tend to be truer than the orange-red of the pond comet. The body of the shubunkin may be a soft blue and the reds that appear on this variety are usually deep red, a color that any koi would be proud to wear.