Pet Keen is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Home > Goldfish > Comet Goldfish: Care Guide, Pictures, Varieties, Lifespan & More

Comet Goldfish: Care, Pictures, Temperament, Habitat, & Traits

Comet Goldfish on aquarium

Goldfish are common choices for aquariums because they are visually pleasing, easy to maintain, and agreeable around other fish. When you pick goldfish, you open up a whole range of possibilities. It might surprise you that there are over 200 different goldfish breeds, all with different charm and appeal.

So, if you’re looking for a few goldfish buddies to add to an existing aquarium or you are starting from scratch, the petite Comet Goldfish should be at the top of your list. Let’s learn all about this little swimmer.divider-fish

Quick Facts About Comet Goldfish

comet goldfish Carassius aurastus comet_smspsy_shutterstock
Credit By: smspsy, Shutterstock
Species Name: Carassius auratus
Family: Cyprinidae
Care Level: Easy
Temperature: 65°–72° Fahrenheit
Temperament: Social
Color Form: Yellow, orange, white, red
Lifespan: 5–14 years
Size: 4–12 inches
Diet: Omnivore
Minimum Tank Size: 50 gallons
Tank Set-Up: Freshwater
Compatibility: Other fish that can’t fit in a Comet’s mouth and can handle lower water temperatures

Comet Goldfish Overview

The Comet Goldfish is an attractive little fish with a single fork-shaped tailfin, unlike many of its cousins. Because of the unique tail, they were named after a comet in space. They aren’t as large as others, either—but they can get up to roughly 12 inches.

Many people love the simplicity of owning Comet Goldfish. They are very easy to care for and look awesome swimming around. There can be some issues with pairing tank mates since Comets like a bit of a cooler temperature.

But there are still several fish that work well alongside the Comet. Comet Goldfish do very well in ponds where they can explore the space. For being such little fish, they sure do love having tons of room to swim—the more, the better.

These beauties are also interesting to watch since they are so interactive and alert. They will add character to your pond or aquarium—permitting that living conditions are compatible.

Let’s get down to brass tacks.

pets 6

How Much Do Comet Goldfish Cost?

Comet Goldfish are commonly used as feeder fish because of their size, so their price reflects that. Most Comet Goldfish are under a dollar per fish—many ranging from $0.20 to $0.50.

You can afford to fill your tank with quite a few Comet Goldfish but be careful about pairing them with fish that are much bigger. Bigger fish can easily view Comets as prey, swallowing them up.

In the same sense, a Comet might mistake existing thank creatures for snacks, too. It goes both ways. So, before you buy several little Comets, ask yourself if your existing fish will be accepted so you don’t waste money or risk aquarium lives.


Typical Behavior & Temperament

Comet Goldfish are active, friendly, and social fish. They are small, but they love darting around the aquarium from corner to corner, sometimes as fast as they can go. You’ll need a tank big enough to accommodate their high energy and big personalities.

Apart from their speediness and playful nature, they are all very neutral and peaceful. They can coexist just fine among others without exhibiting aggression or territorial behavior.

They can even recognize you and play with you through the aquarium glass by following your finger or darting behind a plant to play hide-n-seek. They are very interactive, both with other creatures and humans—most of the time.

Even though they blend very well temperamentally, their living conditions are usually what makes them incompatible with other fish—not their nature.

Red comet goldfish white fish_Mohamed Nageeb Nasr_shutterstock
Credit: Mohamed Nageeb Nasr, Shutterstock

Appearance & Varieties

Comet Goldfish don’t get nearly as big as some other goldfish varieties and they have their own look, too. They have many similar colors and patterns to their goldfish cousins, but their overall body and fin shape differ quite a lot.

  • Singular V-shaped Tailfin: The notable tail of the Comet Goldfish is exactly how they got their name in the first place. It’s arguably their most recognizable feature.
  • Wedge-Shaped Dorsal: The dorsal at the top is short, arching downward on the spine.
  • Slender Body: Many goldfish have pudgy middles, but that isn’t the case with the C They have thin, narrow bodies instead.  
  • Color Varieties: Comets have solid-colored bodies ranging from white to red. The more vibrant Comets can lose color with age or poor diet.
  • Spotted Varieties: Some Comets can have spots of different colors on them, too.

pets 6

How to Take Care of Comet Goldfish

Habitat, Tank Conditions & Setup

  • Tank/Aquarium Size: For one Comet Goldfish, you’ll want to have at least a 50-gallon aquarium. You’ll need to add 10 to 12 extra gallons per additional fish. Ideally, a Comet would be most happy in a tank 75 gallons and above.
  • In all reality, the Comet would love swimming limitlessly around a pond if you have one. They are hardy little fish that can tough out colder waters, which is a compatible aspect of pond-dwelling.
  • Water Temperature & pH: It’s very important that the water stays cool, so make sure that you keep the tank out of the heat and away from direct sunlight. The water needs to stay between 60° and 70° Fahrenheit with a pH of 7.0 to 8.4.
  • Substrate: There are a few types of substrate you can use for your Comet. Sand encourages natural foraging and has a very natural aesthetic. Some argue that sand can get in their gills, causing irritation, but there is no definitive evidence on this.
  • Gravel has many color selections: It easily anchors plants and décor, but it isn’t always the best type of substrate. As they eat from the bottom, they can ingest smaller pieces, which can cause blockages in their digestive tract.
  • Plants: Plants are very good for filtering water in the tank. Some compatible plants for Comet Goldfish tanks are:
    • Java fern
    • Java moss
    • Onion plant
    • Crypts
    • Amazon s words
    • Duckweed
    • Pothos
    • Anubias
  • Lighting: Comet Goldfish don’t need heat lamps, but they do need appropriate light cycles. Their aquarium should mimic the natural day/night sequence. So, always make sure to provide light for 12+ hours a day, followed by appropriate darkness.
  • Filtration: Comets absolutely need to have filtered, highly oxygenated water, otherwise they can be susceptible to bacteria and illness. A regular canister filtration system works fine with these fish, but the water will need to be cycled multiple times per day to keep things fresh.
comet Carassius aurastus comet_smspsy_shutterstock
Credit: smspsy, Shutterstock

Are Comet Goldfish Good Tank Mates?

This is a loaded question because temperamentally, Comets are excellent—therefore compatible with a wide range of fish. But they prefer much colder water temperatures than most, so living together isn’t really in the cards sometimes.

Also, because of their smaller size, you need to be cautious about who else is in the aquarium. Some fish can mistake these tiny guys for food. Alternatively, they’re pretty voracious eaters who won’t mind making a snack of the small tank snail sluggishly sliding around.

But that doesn’t mean you can’t get some friends for your comet buddies.

Comet Goldfish pair well with:
  • Rosy Barbs
  • Weather Loaches
  • Zebra Danios
  • Bristlenose Plecos

What to Feed Your Comet Goldfish

Comet Goldfish can eat a variety of fresh foods as well as manufactured fish food flakes. Flakes and pellets have all of the nutrition that your comet needs included in the recipe, so this can work as an everyday diet.

But also make sure to give your comet a variety of fresh, cooked, or dehydrated food. You can also feed them nutritious gut-filled insects like earthworms, bloodworms, and larvae. They won’t hesitate to gobble up live food snacks.

Many goldfish die as a result of improper feeding, diet, and/or portion sizes – which can be easily prevented by proper education.

The Truth About Goldfish New Edition

That's why we recommend the best-selling book, The Truth About Goldfish, which covers everything about goldfish nutrition, tank maintenance, illnesses & more! Check it out on Amazon today.

Other fruits and veggies they like:
  • Shelled peas
  • Cucumber
  • Broccoli
  • Lettuce
  • Carrots
  • Blueberries
  • Strawberries

If you have live plants in your aquarium, these fish will love feasting on algae and plant matter, too.

Comet Goldfish_Vangert_shutterstock
Credit: Vangert, Shutterstock

Keeping Your Comet Goldfish Healthy

Little Comet Goldfish are quite hardy fish that stay healthy easily—in the right conditions, of course.

Keep your comet living their best life by:
  • Providing heavily filtered, oxygenated water sources
  • Live plants for food and extra oxygen
  • An omnivorous diet of pellets, live, and fresh foods
  • Pairing with only compatible fish types
  • Keeping water temperatures cool and the environment clear


Breeding the Comet Goldfish in a tank setting is not an easy feat to accomplish. You have to have extremely specific environmental factors for successful hatching. Breeding these goldfish are much more likely to be successful in ponds where nature takes its course.

But if you decide to try a tank, Comets require a trigger to start breeding, which usually involves a temperature drop to 58° Fahrenheit and only 8 hours of light for a month.

To prepare for healthy breeding, make sure to offer them a substantial diet to make up for the energy impact on their bodies. Include live foods, frozen foods, and standard flakes and pellets so they maintain a well-rounded diet.

Once the month has passed, slowly raise the temperature back up to roughly 70° Fahrenheit. You must do this slowly, otherwise, you can stun or kill your fish. Also, increase the light back up to 12 hours per day.

Once the conditions are right, males should start to encourage the females to lay eggs. They can lay up to 1,000+ eggs at a time, at which point the male fertilizes them. You have to remove both parents until the eggs hatch between 24 and 48 hours later.


Our Final Thoughts

If you have other compatible fish, or you’re just creating your set-up, Comet Goldfish can be very rewarding to keep. They are even-keeled, active little fish that can keep you entertained with their fast pace and alert personalities.

But, the Comet won’t be for everyone. They don’t always work in every aquarium and might not be the best additions to many circumstances. Conduct thorough research to find out if these little guys are compatible with your tank.

Featured image credit: agus fitriyanto suratno, Shutterstock

Our vets

Want to talk to a vet online?

Whether you have concerns about your dog, cat, or other pet, trained vets have the answers!

Our vets

Before you go - Don't miss out!