Which Goldfish Should You Put in Your Pond? Comets, Shubunkins and Commons Compared

by Tory Jon | Last Updated: October 20, 2026

For most pond owners, choosing between common goldfish, comets and shubunkins comes down to appearance. All three have broadly similar care needs, so you can choose the look you enjoy as long as your pond has room for them as adults.

What these three goldfish have in common

All three are varieties of the same species, Carassius auratus. Their colors and fins differ, but they share the same basic needs for clean water and room to grow. Goldfish are social fish, so keep them with suitable companions without crowding the pond.

These are streamlined goldfish with single tails. A comet's tail has two pointed lobes, but it is still one tail fin. Round-bodied fancy goldfish, such as many fantails and orandas, have a different build and often swim more slowly. That makes swimming ability and access to food more useful compatibility checks than color.

There is little reason to choose a common over a comet because you expect a calmer fish, or a shubunkin because you expect better cold tolerance. Health, breeding background and pond conditions are more useful guides than a claimed hardiness ranking among these three.

Common goldfish, comets and shubunkins compared

A useful adult-size guide is about 5-9 inches (12-22 cm), based on the usual goldfish length reported by Animal Diversity Web. This is a broad range for the species, rather than a separate size limit for each variety. The source does not specify whether its measurement includes the tail.

Body length excludes the tail fin; total length includes it. A comet's long tail adds to its total length. Larger fish are possible: goldfish can reach about 12 inches (30 cm) in body length. Plan for growth beyond the usual range rather than judging the space needed by the small fish at the store.

Feature	Common goldfish	Comet	Shubunkin
Color	Often orange or red; white and mixed colors also occur	Often orange, red, or red-and-white	Calico patches, often with dark speckles and blue-gray areas
Body and tail	Streamlined body with a relatively short tail	Slim body with a longer, deeply forked tail	Streamlined body; tail shape varies by strain
Adult size (general guide)	About 5-9 in (12-22 cm); larger fish are possible	About 5-9 in (12-22 cm); larger fish are possible	About 5-9 in (12-22 cm); larger fish are possible
Care requirements	Clean water, oxygen, compatible company and open swimming space	Same basic needs as commons	Same basic needs as commons
Why choose it?	A classic goldfish shape with bold color	A flowing tail that stands out as it swims	Mottled color and individual patterns

Choose commons for a classic pond look

Common goldfish have a familiar shape with a shorter tail than a comet. A bright orange fish can be easy to pick out against a dark liner, which is useful if you usually watch the pond from a patio rather than right at the edge.

Look at the actual fish before buying. Common goldfish come in more than one color, and a young fish's coloring may change as it grows.

Choose comets for their longer tails

A comet's main attraction is its longer, deeply forked tail. You may especially enjoy that shape when watching fish turn near the surface.

Allow open swimming room so that the tail can move freely. A small comet still needs room to grow.

Choose shubunkins for patterned color

Shubunkins bring a mottled, calico look instead of large areas of one color. Their patterns can make individual fish easier to recognize when you watch them up close.

Tail shape varies among shubunkin strains. Some have shorter tails, while others have longer or broader ones. Ask to view your choices from above, since that is how you will usually see them in a pond. Choose the individual pattern and shape you like rather than relying only on the variety name.

Can you keep all three together?

Yes. Healthy commons, comets and shubunkins generally make suitable companions because they have similar body shapes, swimming abilities and water needs. A mixed group is a reasonable choice if you enjoy both plain and speckled colors.

They can also breed with one another because they belong to the same species. Goldfish scatter eggs and provide no parental care. Some young may survive in a planted pond, so leave capacity for possible offspring. A mixed group will not reliably produce babies that match one parent's named variety.

If you already keep slower fancy goldfish, take more care. Fast single-tail fish can reach food first, leaving slower fish short of their share. Check swimming ability and feeding access before combining them.

What if you already have koi?

These streamlined goldfish can share a suitable pond with koi. Your pond needs room for the koi's adult size as well as the goldfish you want to add. As aquatic veterinarian Jessie Sanders explains, koi need considerably more space than goldfish. Feeding competition can become more noticeable as they grow.

Avoid adding tiny goldfish that a larger pond fish could swallow. At feeding time, check that the goldfish actually eat rather than simply gathering beside the koi. If the pond is already crowded, changing from commons to shubunkins will not create spare capacity.

Buy for the pond you can support as the fish grow

A few small fish can look lost in a new pond. Resist filling that empty space all at once. Adult fish need more food and produce more waste, while surviving babies may increase the population without another trip to the store.

No single gallons-per-fish formula fits every backyard pond. Water volume helps, but usable swimming space and oxygen also affect capacity. Filtration must handle the waste from the whole group. A filter's advertised pond size is only part of that decision.

Before buying, make sure the pond's biological filter is established. This is the part of the filter where helpful bacteria process harmful fish waste. Ammonia and nitrite should read zero on a working test kit; a detectable result calls for correcting the water problem before adding fish.

At the seller, take a few minutes to watch the group:

Choose fish that swim upright and move without struggling.
Pass on fish with visible sores or damaged fins.
Avoid buying from a group where fish are gasping or repeatedly rubbing against surfaces.

Arrange a separate, filtered quarantine setup before bringing new fish home. Keeping newcomers apart initially reduces the chance of introducing disease to the fish you already own.

Will they be able to stay outside in winter?

Healthy commons, comets and shubunkins can overwinter outdoors where the pond maintains suitable conditions. Choosing among these three rarely changes the winter plan as much as choosing between streamlined goldfish and more delicate fancy varieties.

Depth alone cannot guarantee survival. Your plan must account for local cold spells and how much unfrozen water remains. Fish also need oxygen and gas exchange through winter. Maintain an opening in the ice so gases can move between the pond water and the air.

Ask a local pond specialist how ponds like yours cope with winter. A shallow or exposed above-ground pond may need an indoor winter arrangement. Prepare that filtered space before freezing weather arrives. If ice forms, avoid hammering it to make an opening.

Which goldfish should you choose?

For a classic look: Choose commons if you like a compact tail and bold areas of color.
For flowing fins: Choose comets if their longer tails are the feature you most enjoy watching.
For varied patterns: Choose shubunkins if you want speckles and calico patches that give each fish a different look.
For a mixed pond: Keep a combination of all three if you have capacity for their adult size and possible offspring.

If your pond already holds healthy single-tail goldfish, appearance can guide your choice. If it holds slower fancy goldfish, or koi that are outgrowing the available space, sort out crowding or feeding problems before adding more fish. The best purchase is a healthy fish you enjoy looking at and can house well for years.