Comet goldfish

Comet goldfish

If you want an elegant goldfish that’s as tough as it is pretty, the Comet Goldfish is for you. Sort of a halfway house between the Common goldfish and the Fantail, the Comet has a sleek, elongated body that ends in a single scissor-like tail.

Indeed, it’s called the Swallowtail goldfish in the Far East, which we think really suits it.

Comets come in several different colours, with gold and metallic fish and the orange-and-red Sarasa Comet amongst the most popular. In prize-winning fish, the colour of the body extends right into the tail; even everyday specimens in the pet shop should show deep, rich colours over most of the body. All Comets start life silvery green, however, which makes buying very young fish rather hit-and-miss.

In ideal conditions Comets can reach nearly a foot in length. Although their growth will be restricted in smaller quarters, it’s only right to give them as much space as you can spare.

Comet goldfish tips:

  • As ever when buying goldfish, look for bright, clear-eyed specimens that take an interest in their surroundings.
  • The tail shouldn’t droop at all.
  • Comets are fast-moving fish that need a large indoor aquarium (ideally at least four-foot in length), or better yet a pond.
  • They are pretty hardy fellows, and will happily live outside in most regions, provided their pond is deep enough for over-wintering.
  • Comets love to shoal, so try to keep 4-6 fish together.

Comet goldfish seem to have been rather overshadowed in recent years by their fancier counterparts, which is a shame. Even purists who worry that man has tampered too much with some varieties of goldfish have to admit that the comet is a splendid creation.

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68 Responses to “Comet goldfish”

  1. Hi i have a comet goldfish (still a baby) in a foot long tank , i wasnt told they get that big !!!

    how long have i got until he does??

  2. how about if the tank is 1 gallon

  3. @Rachel - Goldfish will grow far more slowly in small tanks than in ponds, but a foot long tank is not going to be a good home for more than a few months. Long-term you’ll need to get a 4-foot aquarium to really give your fish the home he deserves, or a pond. Fancier varieties such as fantails are better for small tanks.

  4. @Ryan - I’m afraid I don’t think a 1 gallon aquarium is suitable for goldfish for more than emergency quarters.

  5. i have several of the very small comets. do they stay this little or do they really get big enough to need a 4 foot tank?

  6. @Becka - your comet goldfish are babies. They will definitely grow larger with good care. In captive aquariums goldfish size does seem to be limited a bit by the size of the tank, but in my view they’re eventually going to need a four-foot aquarium to be happy.

  7. i have my goldfish in a 4 gallon tank.. is this going to be enough for him for now? until i can afford- and have space for- a larger tank as i’m moving in about 4 months.

  8. Can someone please help me?!? I’m planning on getting my first goldfish soon and I was just wondering, does a comet goldfish need to live with other fishes like a Fantail?

  9. I have one comet and 2 shurbunkins together in a 30 gallon tank. They get on really well because they are all fast swimmers - in fact, they seem to play “tag” together.

    I did have a comet with a fantail but the fantails are much slower. Pretty, but not as interesting to watch as comets.

    For sure, have at least 2, so they are not bored. But remember, they do grow. My comet is 6 months old (well, plus whatever age it was when I bought it) and is already 4 inches long. And at 2 months, the shurbunkins are about 3 inches, including tails.


  11. Hi i used to have a Common Goldfish and a Comet but the Common Goldfish died 1 month ago. They got on really well i think he died of age. I still have my Comet, he is 1 year old and he’s in a 12 gallon fish tank but i’m going to save up to get a 60 gallon one!

  12. Hi! I have a Comet Goldfish! His name is Nemo! I am looking forward to giving him the best care he needs.

  13. i had a comet goldfish that was 8 inches and probably 10 with the tail in a 55 g thats why it greww that much

  14. I have 2 comet goldfish in a 1 gallon tank I want to get a bigger tank but I don’t have the money for one what should I do.

  15. I have just bought a black moor and a comet and have them both in a 10ltr bowl which i believe is about 3 gallons, i was told by the guy in the petstore that this would be ok, but after reading alot of the posts this does not seem so, especially for the comet, what about the black moor would that be ok, hope some one can help.

  16. I’m getting to comet goldfish for my science fair project that I’m doing. I’m trying to find all the information that I can about comets. This is great information.

  17. i like u

  18. I Have a couple questions. i have 2 comets. the one is 6 years old and the other is 5. they had 2 sets of babies this summer. they are all brown. how old do they have to be to start changing colors?

  19. i am getting a fish tank and a couple of comets for my birthday in about a week. is a 20 gallon tank big enough for both of them?

  20. I have a 60gal. SetUp (4′L x 2′H x 1′D) The plan is to get One Comet Goldfish and One Sarasa Comet Goldfish. My question is Ive seen pics and in some pet stores “Common Goldfis” and “Comet Goldfish” Are they the same fish or are they just mis-labled at the pet store??

  21. @Marc…

    Are you looking in the “feeder” tanks like at Petsmart? They have them labeled as comets but I believe they are mixed with commons and comets.

    I actually just got 6 fish from the “feeder” tank at my Petsmart. Some real pretty ones. .27 cents each. They all appear to be healthy as well. I have them in a 72 gal. bowfront but plan to move them to a pond (if I get it built) by next spring.

    But they are lovin’ their new home right now. My tank measures 4 ft long, 12″ on the sides and bows out to 18″ in the center. The tank is 22″ deep.

    I believe the comets are gonna have longer tails? I got one I believe might be a common goldfish as it doesn’t have the long tail fin. But I couldn’t pass him/her up. A beutiful red on top, white on bottom fish.

    I love these fish. I wish I could build a huge pond and just buy all of them. I hate it they are used as “feeder” fish.

  22. While I’m no expert, I still think you should have a 55 gal and up for these goldfish. They are swimmers. You may see them in the pet store, a bunch in a small tank, but that’s not meant to be a permanent home.

    It’s like this. If you really want a goldfish, be able to provide it with the proper care it needs. Just cause you see them in bowls or small tanks, doesn’t mean it’s right. Another fact, the larger the tank the easier it’s gonna be to take care of as far as water quality goes.

    My goldfish love to play in the current from my filters and the bubbles from the large 12″ airstone. I have 2 penguin 350 filters on a 72 gal bowfront (really only 65 gal of water after substrate/decor). So that’s over 10 times GPH. I have enough filtration for a 140 gal tank and only 65 gal of water. Good filtration is another big plus with keeping goldfish.

    I read its a myth that a goldfish grows to the size of their tank. What happens is, you stunt their growth by putting them in small tanks. Their organs continue to grow. I believe this causes them to die a young age.

    The pond I’m building is gonna be 8 ft long, 4 ft. wide, and about 2 ft. deep. Should probably be close to 500 gal.! I plan to only have comets and shubunkins.

  23. The body shape of the Comet is long and slim. They have a high dorsal fin and deeply forked long and narrow caudal fins. Comet has a tail lobes like open pair of scissors with metallic scales which is distinct feature from other goldfishes. It has single anal fin and long& pointed pair of pelvic, pectoral fins. Comet is fastest swimmer among all Goldfish varieties.

  24. I have 4 comets in a 4.26 Gallon tank (21 Liters)

    is that bad

  25. I have 6 comet goldfish I got the other day, for my science fair project, and I plan on keeping them, I wanted to research them and what size tank I need, as they were crowded ina small tank at the pet store. Thank you so much for your advise!!

    Also, one of them died last night, I had them in tubberware bowls(very permanent, this is just until I move them to my other house and get them a bigger tank.) I had them all lined up behind a George Foreman grill, so ass to keep my cat away, and my dad told me one was on the floor this morning(cuz lastnight they kept flopping out of their bowls) and he flushed him, and I was thinking of getting another one or two to keep the others company, tell me this will the 4 foot tank be big enough to hold all the fish, and how long to they live?

  26. By the way, “ass” is a typo, sorry, and we fixed the problem with them flopping out.Also, can Comets be paired with other fish? I would just like to know, too, at what age can you really begin to tell which ones are male and which are female? I was kind of planning on breeding sometime, but keeping them seperate for now would be a good idea. Do the “feeder” Variety get as big as the others?

  27. hello i am wondering I have and 1 and a half foot long would that be a good for a full grown comet fish?

  28. I bought 6 comet goldfish and i have them in a 10 gallon tank is there a way i can keep them small enough to stay in the tank?
    and 4 of them have already died in the past hour and 30 min can anyone give me advise

  29. Hi Andrea. Im a 1st timer and owns a 20l tank. I bought 2 comets 5 days ago and they are doing very well. They had their first treat of bloodworms yesterday and they absolutely loved it. 2 important things i remember having to ensure before adding the fish in tank, 1) is to prepare my tank environment for a good 5-7 days prior to getting the fish. 2) only add 1-2 fish to begin with and add another one after abt a week and another one in another week. I wad told that my little beginner fish tank is only suitable for 2 comets. And no more. By adding 6 fish at once, your aquarium ammonia level must have sky rocketed and kill them. Imagine 6 fish in a 10 gallon tank, u were only giving each fish less than 2 gallons of water to live in (eat, sleep, space etc.) think of it as a home for yourself and family :) i added some little aquatic plants, little flat rocks and a drift wood to make my tank as natural as possible and ensuring the quality of the water and oxygen is at a good level. My advice is start small, get to know the fish, and read lots, just like what i have to do right now. :) All the best!

  30. I bought 3 comet’s a month a go. i went back to but another 3, i relised how fast these fish grow. i now have 9 comet’s in a huge pond out side on my patio :-)

  31. I have a comet goldfish that I got at a fair. Right now he is in a 1 gal. tank. I want to switch him over into a much larger tank, along with getting another goldfish, probably a black moor. How large should my fish tank be?

  32. I got a comet goldfish from PetSmart. I found this website a couple weeks after I got it. I want to point out that comet goldfish tips 3 and 5 are not correct. I keep my goldfish in a fishbowl (which is really a big pickle jar), and it is doing just fine in there. my goldfish doesn’t really care if there are no other fish around, because I always talk to it and keep it company. It was a small one, so it was only 13 cents. The goldfish was about 1-2 years old. I can’t tell if it is a male or female, because it is too young to tell. The clerk said that in a couple years, if its tail stays the same, it’s a female, but if its tail grows into a fan shape, it’s a male. i think it’s a male. -EarthBoundFan985

    P.S I named the goldfish Cheddar. Cheddar is black, white and orange. I don’t know what breed of comet goldfish it is. When I got it, the tank he was in just said Comet Goldfish (SM)

  33. i like goldfish :-)

  34. i just got 5 baby comet goldfish is a 10 gallon ok

  35. i just got 4 baby comet goldfish.they all live in a 1 gallon bowl!!!!!!!!!!!!!!!!!!!!

  36. Adam u have problems

  37. and u dont. ur username says u love to eat toenails for dinner.u have nothing to say.

  38. i have 2 fish in a 20L tank and they love it


  39. bobby

  40. HI

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  42. adam u really truly are weird. Im the only kool kat.

  43. I like fish

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  47. My comets are in a one gallon tank I made the mistake of getting one it was not good so I bought three more they were very happy

  48. I have three comets and I have had them for six years and never had a problem

  49. I have four comets in a one gallon tank what size tank would be best

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  55. I have 2 comet goldfishes they live outside in 55 Gal rain barrels one is in one and the other is in the other, they are growing fast because they are eating algi, and mosqitoe larva. My question is what will the winter bring, when the water freezes will they die or freeze and come back to life. How many can I keep in the barrel?

  56. I have a goldfish and comet they are like best friend’s

  57. I have a goldfish and comet they are like best friend’s they like to play races!

  58. I have a comet and goldfish they are like best friend’s they also like to play races! Lol😜

  59. They get big 4 to 6 inches

  60. I have a comet and,goldfish they play races and are buddies! Lol🙌

  61. I had 1 comet for about 1 month and I just got a new one. That is twice the size, my first one is picking on the new one, as in biteing

  62. Hi my tank is 12 /8 and 8 high I have one comet fish how many could I have in this tank?

  63. Hi😆 I have a shubinki and a sarsa comet fish in together.They have been in together for 1 year.I bought 4 new fish yesterday.They are small enough with big eyes.If I mix the old fish with my new fish will they fight eachother?

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  65. I have tetra fin gold flakes food. I have one comet about
    1 1/2 inches long. This is my 4th time comet fish that I
    bought. I don’t know what to do. I’ve got flake food but I’m not
    sure he’s eating the flakes. What’s wrong. My email address please let me know. Thank you Karie Martin

  66. I bought a comet and within a week it died. Then again I bought
    another comet and it died too. I have a 5 gal tank. One comet
    at a time in the tank. I bought a third it died too. Why is that.
    My email is

    Thank you Karie Martin

  67. I have one comet goldfish. Is a 2.5 gallon ok? I know I need a bigger tank but he is a baby so…

  68. Hi i have a Blagdon Affinity pond with 6 windows the biggest one u can buy, i have at the moment 2 red comets, 2 shubunkins, 5 gold fish is that enough or could i add more in the summer please Thank You x

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