Comet Goldfish

About the Comet Goldfish

The Comet Goldfish is one of the most iconic and hardy goldfish varieties, renowned for its streamlined body, long flowing single tail, and energetic swimming behaviour. Originally developed in the United States from the Common Goldfish, the Comet is now one of the most popular choices for outdoor ponds and large freshwater aquariums.

Available in a variety of colours including bright orange, red, white, yellow, calico, and bi-colour patterns, Comet Goldfish are admired for their speed, graceful movement, and exceptional hardiness. Their long, deeply forked tail gives them an elegant appearance as they glide effortlessly through the water.

Comet Goldfish are highly social and should be kept with other single-tail goldfish such as Common Goldfish and Shubunkins. They require spacious aquariums or ponds with excellent filtration due to their large adult size and high waste production. A varied diet of premium goldfish pellets, fresh vegetables, gel foods, and frozen treats will help maintain vibrant colours and excellent health.

Hardy, active, and long-lived, the Comet Goldfish is an outstanding choice for ponds, large aquariums, and beginner fishkeepers.

Quick Care Guide

Scientific Name

Carassius auratus

Common Name

Comet Goldfish

Origin

Captive-bred ornamental variety developed in the United States

Adult Size

20–30 cm

Temperament

Peaceful

Diet

Omnivore

Minimum Tank Size

200 Litres (single fish)

Temperature

10–24°C

pH

6.8–8.0

Water Hardness

5–20 dGH

Difficulty

Beginner

Lifespan

15–20+ Years

Suitable For

Large aquariums, outdoor ponds, and coldwater aquariums

Frequently Asked Questions

How large do Comet Goldfish grow?

Comet Goldfish commonly reach 20–30 cm, with some pond-kept specimens growing even larger under ideal conditions.

Can Comet Goldfish live in ponds?

Yes. They are one of the best goldfish varieties for outdoor ponds thanks to their hardiness, active swimming, and ability to tolerate seasonal temperature changes.

What do Comet Goldfish eat?

They thrive on premium goldfish pellets, gel foods, blanched vegetables such as peas, spinach, and zucchini, along with frozen bloodworms, brine shrimp, and daphnia.

Can Comet Goldfish live with Fancy Goldfish?

It is not recommended. Comets are much faster swimmers and often outcompete slower fancy goldfish such as Ranchus and Orandas for food.

How long do Comet Goldfish live?

With proper care, excellent filtration, and a spacious environment, Comet Goldfish commonly live 15–20 years, with some exceeding 25 years.

Common Mistakes

Keeping them in bowls

Comet Goldfish grow very large and require spacious, filtered aquariums or ponds to thrive.

Mixing them with Fancy Goldfish

Their speed and activity can stress slower fancy varieties and prevent them from feeding properly.

Underestimating their adult size

Many juvenile Comets are sold small but quickly outgrow undersized aquariums.

Poor filtration

Goldfish produce significant waste and require powerful filtration along with regular water changes.

Overfeeding

Excess food contributes to poor water quality, obesity, and digestive problems. Feed only what they can consume within a few minutes.