How to take care of a comet fish?

We will talk about comet fish care in this blog post. We will also discuss important factors such as their habitat,types,lifespan,tank set-up, water parameters and healthcare, etc.Everything you need to know about comet fish care will be briefly discussed.


In this blog

  • Key specifications of comet fish
  • Why is comet fish care important?
  • How many comet fish should you start with as a newcomer?
  • Habitat of comet fish
  • Types of comet fish
  • Different strains or colors of comet fish
  • General and physical attributes of comet fish
  • Comet fish lifespan
  • Comet fish tank set-up
  • Comet fish diet and feeding requirements
  • Comet fish healthcare and health conditions
  • Comet fish daily care and Bi-weekly care tips
  • Summary

How to take care of a comet fish?

Daily care tips for comets fish. 

  • Snails can be added to reduce algal growth in the tank.
  • Comets should be fed 2-3 times a day.
  • Defrost frozen food before giving them.
  • Don’t overfeed them,they are prone to bloating.
  • Rotate their diets to give them balanced nutrition.
  • Remove uneaten food everyday using a gravel siphon to avoid ammonia poisoning.
  • Temperature should be monitored from time to time.
  • Don’t add sharp or edgy decorative items in the tank, this can damage their beautiful long tail.
  • Observe their swimming patterns and feeding habits, if they are not swimming properly & not accepting food then kindly transfer them to a separate tank until they recover.
  • Make a habit to check tank equipment on a daily basis to know if they are working properly or not.

Bi-weekly care tips for comets

  • Water changes- 25-30 percent water should be changed weekly to reduce the bioaccumulation.
  • Don’t change water frequently as it kills beneficial bacterias.
  • Filters should be used to remove waste from the tanks.Its extremely important.
  • Wash filters once or twice in a month properly with a good quality scrub.
  • Quarantine new tank mates at least for a week or two in a quarantine tank to avoid spreading any kind of disease.
  • Separate ill tank mates to hospital tanks for a week or until they recover.
  • While feeding live food, take measures because they might be wild caught and can come with a wide range of diseases.
  • Quarantine live food for 2 weeks in a separate tank before feeding them.

Key specifications of comet fish

Scientific nameCarassius auratus auratus
HabitatFreshwaterUnited states 
Lifespan4-14 years
Body sizeBody shapeColor
Special trait
Sexual dimorphism
Upto 12 inches in length (fully grown)Slender bodyOrange and yellowLong caudal fin,forked tail fin (resembles tail of comets)Yes
Another namesComet-tailed goldfishPond comet
Optimum temperatureOptimum pHWater hardness60F-70F6.5-7.5 Soft to Hard
TemperamentBeginner / experienced Peaceful and hyperactiveIdeal for both
Care levelEasy to medium
Tank size and set-upTank type (Prefered)50-75 gallon tankPlanted tankCommunity tank
Preferred plants/decorationsLive and succulent plants
CompatibilityKoi and other goldfish
Number of comet fish species found Sarasa comet variantTancho single-tailHybrid comet
BreedingNo of eggsProlific breedersUpto 1000 eggs

Why is comet fish care important?

Comets are like their cousins, common goldfish when it comes to eating.They are aggressive eaters,their care is extremely important in aquarium conditions,because they eat like anything and this can lead to the accumulation of ammonia in the tank which could deteriorate their health.

How many comet fish should you start with as a newcomer?

While choosing comets make sure that all their fins are single except the pectoral and pelvic fins, the tail fin should be long and ideally more than ¾ of the length of the body.

All their fins should be pointed and without holes and overlapping. They are a great pet to keep in a pond or even a larger tank because of their hardiness.As a beginner you can start with a 20-30 gallons tank.

Habitat of comet fish

Comets are hardy fish and are selectively bred(crossing between veiltail and common goldfish) basically for the home aquarium over a long time.They were bred for the very first time by Hugo Mulertt in Washington, D.C (USA).

Types of comet fish

  • Sarasa comet variant -They strictly come in these two colors,red and white. They look very much like koi fish, so don’t get confused.
  • The tancho single-tail variant. 
  • Hybrid comet (Black variety) – Pseudo goldfish

Different strains or colors of comet fish

Comets come in a variety of colors unlike the common goldfish.The brown ones change their colors with age.

  • Standard colors- Yellow-orange and orange-red
  • Other colors- white, brown, yellow, red-white, black

General and physical attributes of comet fish

  • Comets are slightly smaller than their cousins, common goldfish.
  • Comets have a long elongated tail fin (forked)
  • They have one anal fin.
  • They have a slender body (for fast swimming)
  • Comets have a long back.

Comet fish lifespan

  • Comets can live upto 4-14 years depending upon the amount of care they are getting.
  • Your comets need the pristine water conditions,temperature, proper filtrations and nutritional diet to thrive well in the aquarium conditions.

Comet fish tank set-up

Tank sizeLight intensitySubstrateWater parametersTemperatureTank plantsTank mates

Tank size for comet fish

  • Never keep them in round bowls,instead get a spacious rectangular shaped aquarium for your comets.Always get a tank with a bigger surface area.
  • They need a spacious tank to play and swim around, so get a 50-75 gallon tank to house your comets. 
  • A single comet can live in a 75 gallon tank.
  • Two comets can be housed in 125 gallons tanks.
  • Additional comet – 50 gallons
  • Tank should be at least 3 ft long for one comet.
  • Don’t over-filter the tank, overfiltration can wipe out beneficial bacterias from the tank.
  • They are aggressive eaters so you should install powerful filters in the tank to remove the bioload.
  • Filter type- Hang-on back or canister filter,as they are easy to maintain.

Light intensity for comet fish

  • Comets prefers moderate to normal lightings
  • They prefer a cool environment.
  • Avoid keeping them in direct sunlight.
  • The light cycle is usually maintained during their breeding time.

Substrate and decoration for comet fish

  • They are not so particular about the substrate.The main role of substrate is to provide a natural environment for comets.Its totally up to your choice.
  • Small gravels, sand or a bare bottom can be used as their tank substrate.
  • Smooth rocks and driftwoods are most common in aquariums.
  • They don’t really care about the decoration, all they need is a spacious area to swim and play.
  • Avoid sharp and edgy decorative items in the tank, as it can damage their long and beautiful flowy fins.

Water parameters for comet fish

  • Comets are freshwater fish.
  • They should be kept in cold water.
  • Water chemistry is not critical other than keeping ammonia, nitrites and nitrates very low.
  • So like all aquarium fish, water changes are a must and weekly water change is recommended
  • Optimum pH – 6.5-7.5 

Temperature for comet fish

Temperature plays a very important role in the metabolism of an organism.Comets are one of the hardiest varieties of goldfish and can survive in low temperatures.

But if you’re living in colder regions or the temperature is below the ideal temperature then it’s better to get a heater along with the aquarium.

Normally they dont require heaters but in more colder regions to maintain the optimum temperature it is advisable to have a heater.Use a thermometer to monitor the tank temperatures.

  • Optimum temperature – 60F-70F (soft-hard)
  • Breeding temperature- 74F

Tank plants for comet fish

Plants are very important for the aquariums as they keep the tank environment lively,improves the quality of water and also acts as a natural purifier.

For comets, live plants act as a meal because it provides extra nutrition to them.Overall plants keep their aquarium clean and healthy.

List of some tank plants:

  • Hornworts
  • Anacharis
  • Succulents like java ferns and anubias  
  • Fake plants
  • Silk plants

Tank mates for comet fish

Tank mates should be chosen wisely for your comets.Compatible tank mates will never harass your comets.

Avoid slower double tailed goldfish varieties,as comets are strong swimmers and will outcompete them for resources.

Avoid tropical fish, because they can’t tolerate low temperatures and avoid fin nippers in their tanks, because they will damage their fins.

List of some of the compatible tank mates:

  • Other goldfish varieties (wakin,watonai,shubunkins,jikin)
  • Barbs (gold and Rosy)
  • Plecos (Bristlenose)
  • Danios (zebra)
  • Dojo loaches

Comet fish diet and feeding requirements

Comets are massive feeders,they become aggressive during feeding time.They are omnivores and will happily accept whatever you feed them.

Feed them a vitamin and carbohydrate enriched diet.Rotate their diets by giving both vegetables and meaty food to maintain their body colouration and overall health.

Feeding frequency:

  • Feed them 2-3 times a day, but never overfeed them.
  • Overfeeding can cause bloating.Discard the uneaten food from the tanks without fail.
  • Bioload could lead to ammonia spikes in the tank and can make them sick.

List of their favorite food:

  • Meaty food (bloodworms, mosquito larvae,small insects,worms)
  • Plant based diet-lettuce, zucchini, cucumber, broccoli, carrots, crushed peas, medallions, algae and fruits like berries.
  • Spirulina based pellets and flakes
  • Hikari goldfish gold prepared food.
  • Omega one goldfish pellets (sinking pellets)

Comet fish healthcare and health conditions

Common freshwater disease-Due to poor water condition temperature fluctuations and overfeeding.


  • Fungal infections
  • Goldfish ich
  • Fin rot
  • Parasitic infections
  • Swim bladder disease


  • Avoid overfeeding
  • Avoid overcrowding
  • Saltwater bath
  • Antibiotics
  • Maintain stable temperatures
  • Water changes to avoid ammonia spikes


Comets are most popular cousins of common goldfish and are considered as one of the hardiest species amongst them.They come in vibrant colors and their tail fin makes them look attractive.

Comets are hyperactive, dareful and playful aquarium buddies.They do well in outdoor settings too.They are called as feeder fish also.

Comets are fast swimmers.They can recognize their owners and remember each and every thing about their tank.They are given as prizes in carnivals.They are inexpensive aquarium fish.

Comets are recommended for both beginner and experienced aquarium fish enthusiasts. 

Frequently asked questions on comet fish care

How to differentiate between a comet and a common goldfish?

They both look almost similar,comets are a little more slender bodied with a long forked tail fin.Common goldfish have a heart shaped tail and comets have a ribbon shaped tails.

Do comets need heaters in their tanks?

Comets don’t require heaters in their tanks.If you’re staying in a colder region then it’s recommended, otherwise it’s not needed. 

What are hybrid comets?

Hybrid comets are not true goldfish.They Come in black colour.They are a mixture of koi and goldfish.