Goldfish size

Red wag platy
  • #1
I know everyone here knows the myth that a goldfish will only grow as large as its enclosure, or something like that. I know this myth is explained somewhere, but I can't seem to find where. Can someone please explain this myth to me and what determines how big goldfish grow. Does bad water quality affect it? Thanks.
 
gremlin
  • #2
I know everyone here knows the myth that a goldfish will only grow as large as its enclosure, or something like that. I know this myth is explained somewhere, but I can't seem to find where. Can someone please explain this myth to me and what determines how big goldfish grow. Does bad water quality affect it? Thanks.

A goldfish will grow to the depth of its container. That doesn't mean it will be happy. Your comet appears to be a beautiful male. Some of mine will come up and take food right out of my fingers. They definitely know who feeds them and when that person walks by...
 
Shawnie
  • #3
IMO fish will grow no matter what their container is..if there's no more room, they will die...it doesn't mean they will stop growing just because they are in a small tank
 
Red wag platy
  • Thread Starter
  • #4
Thanks shawnie, but this didn't really answer my question. What I'm wondering is what determines how big a goldfish will grow? I've seen goldfish that have stopped growing at three inches and ones that have grown to 6 inches. Is it favorable conditions?
 
sirdarksol
  • #5
Like with humans, a variety of factors will influence the size a goldfish grows to.

Goldfish will continue growing throughout their long life, though this growth slows at a certain point.
A healthy goldfish will grow quicker. The biggest influence on this is the nitrate level in the surrounding water. This is why goldfish will seem to stop growing in a small bowl. They haven't stopped, but their growth has been severely stunted in the same way that a human child exposed to large amounts of toxins will likely have stunted growth. There is also the belief that certain organs may continue to grow, eventually leading to a painful death as the organs crush each other.
Note that mental stress will likely make the goldfish less healthy. Goldfish are smart enough that they need a bigger tank, even if the water quality is somehow kept pristine. They will stress out if kept in a little 10 gallon tank.
Genetics play a part, too. Some of the fancier goldfish have a slower growth rate than the comets. Like in humans, different specimens from the same line will have different growth rates.

I have a goldfish whose growth had stalled out. He was living in a little 20 gallon tank (the previous owner of the tank didn't know anything about keeping fish, and neither did I when I adopted the tank) with numerous other tankmates. He is currently in a 30 gallon tank with a koi, and has almost doubled in size since the move. The two will soon be moving to a 200 gallon tank which will likely be their permanent home (unless either the walnut tree or the pine tree comes down in my back yard, in which case I'll have space for a pond). I expect that he will continue to grow for the next twenty or so years, and I'll have a darn huge goldfish by the end of that time.
 
gremlin
  • #6
the depth of the water is a factor also. My pond and my sister's pond are about the same size length and width. her pond is twice as deep as mine. Mine has a better filter system on it. Both of us started out with fish less than 3 inches long. her fish grew to be about 1/3 bigger than mine. I agree that there are a lot of different factors that can affect their growth, but at least with the basic 'feeder' comet goldfish, depth of the water does play a part in how fast/big they grow.
Koi, on the other hand, continue to grow no matter what depth their tank/pond is.
 
sirdarksol
  • #7
I have seen no such information on this. In fact, the information I have found contradicts any concept that the size of a body of water directly affects goldfish growth. There is no mechanism in the goldfish's physiology that restricts the creature's growth.
I would bet very strongly on some other factor being involved, perhaps even being indirectly related to water depth, such as exposure to sunlight, types/amount of micro-organisms growing in the pond, the previously mentioned depression, etc...
 
Red1313
  • #8
So I'm hoping to go and pick up some new goldies to QT today and I thought I'd ask a question first. Charlie is getting fairly large (3" or so) so should I be looking for new guys that are near his size? I saw some pretty cute babies last night that were only a couple cm long and I'm thinking that would be too small... yes or no?
 
midnightwolf
  • #9
I don't know if this will help much but I have a large goldfish about 6 in or so and I bought 2 smaller ones about 1 in and he has nerer tried to eat them, I think it may just depend on how often your fish ar fed and their behavior. goodluck with your goldies
 
gremlin
  • #10
I have added 1 inch long goldies to a pond that has 11-12 inch long goldies with no problems. I think once the young goldies reach about 3/4 - 1 inch long, they then look enough like goldfish that the larger ones no longer consider them food. Also, as long as there are plants for the younger ones to hide in, and they are all sufficiently fed, you shouldn't have a problem.
 
shellbell4ever
  • #11
I have seen many tanks with all different size gf in them so long as it won't fit in anothers mouth (LOL)and besides watching the babies grow is half the fun imo
 
TedsTank
  • #12
No problems......Goldies, Koi etc. are not predatory fish....if you have a sick fish they might try but even doubt that. I put guppies in my koi pond every year, what a hoot. The goldies leave them alone and occasionally the Koi will stalk them.....but can't catch them so give up.
You can mix different sized goldies with not much to worry about except their eventual size.
 
Red1313
  • #13
Oh good to know
 
Tony G.
  • #14
so red, when are you gonna get them?
 
Red1313
  • #15
lol soon I hope
I don't have a car and right now that's putting a cramp in my stocking plans... However if I can get to Home Depot tonight Petland is right next door...>
 
Tony G.
  • #16
LOL good luck!
 
Red1313
  • #17
Thanks lol
the QT's are set up and waiting 1 for Goldie babies and 1 for Tiger Barbs
 
Linny au
  • #18
Heya I'm relatively new to fish keeping and I have 2 fish..One is a china doll and the other is a calico fantail I think. I was just wondering about what size these 2 are expected to get to. I have them in a 2 foot tank atm but will be moving them to a larger one soon. Thanks to anyone who can give me info ;0
Photo 8.jpg
Photo 7.jpg
 
sirdarksol
  • #19
Heya. Welcome to Fishlore!
Goldfish can grow to be pretty darn big. Even the fancy ones can outgrow most tanks. I've seen a fancy goldfish that was nearly the size of a softball. I've seen regular goldfish that were about a foot long, and I've seen pics of members' goldfish that were even bigger.
 
AshWolFF
  • #20
Since both are fancy goldfish I suggest a 40 gallon long aquarium with double filtration. If you purchased a 55 gallon you could add 2-3 more additions provided that you had plenty of filtration and are good on water changes.

EDIT: Comet Goldfish can get about 2 feet in length (My comet reach maximum size in my 250g pond in practically a couple of months!) similar to Koi and Fancy Goldies can get about 8-10 inches in size. Lionheads can reach 10 inches quite easily (I've had a few of those in my lifetime) while fantails and ryukins are a bit smaller.
 
Linny au
  • #21
wow the calico looks like a little footy already hes a fatty lol. The china doll is impossible to find info on. Hes growing every day, but ive also heard they might be a small species. Also if anyone can guess a sex that would be great but I'm guessing the are very young
 
Linny au
  • #22
and all this gallon talk HAHA ill have to convert it. we go by litres here
 
AshWolFF
  • #23
Terribly sorry. Is about 40 gal = 151 liters. I normally just say gallon's because a lot of people on here use that much more often. Yes, the China Doll Goldfish (surprising you found one) will more then likely only hit the 5-6 inch mark while the fan tail will hit 8-9 inches at most.

As for sexing them you won't be able to do that until they are mature.
 
sirdarksol
  • #24
I would question the claim that China dolls max out at 6". Doing a search for them, there's not a lot of reliable info, and the listed maximum size has seemed to grow over time. Claims from 2004 were saying it would max out at 2". Five years ago, it was 4". Now it's 6". I'm not saying that it won't stop at 6", just that, at this point, I wouldn't count on it.

As far as the fantail goes: yeah, it maxes out at 8-9", but its girth means that it has a much higher bioload than a typical 8" fish. Add to this the fact that goldfish produce a large quantity of nitrogen, and the bioload goes even higher. I personally would not keep a fish this size in anything smaller than a 55g, simply because of how quickly the water could foul (filtration will reduce the ammonia to nitrites and the nitrites to nitrates, but you'll still have a buildup of nitrates in the tank.
 
Linny au
  • #25
haha don't be sorry. I'm the one who has to adjust to the way you guys talk since its an american ( I think) site The china doll is often supplied in my little local petshop. I feel terrible I just googled and it seems my 2 ft tank is only 60 litres. I will def upgrade and I'm happy with just the 2 fish. I do a 25% water change 2-3 times a week. Usually I do 1-2 a week but we are having a heat wave so I am keeping the water cool. Thank you so much for your replies. Its good to know what I'm in for
 
AshWolFF
  • #26
I would question the claim that China dolls max out at 6". Doing a search for them, there's not a lot of reliable info, and the listed maximum size has seemed to grow over time. Claims from 2004 were saying it would max out at 2". Five years ago, it was 4". Now it's 6". I'm not saying that it won't stop at 6", just that, at this point, I wouldn't count on it.

As far as the fantail goes: yeah, it maxes out at 8-9", but its girth means that it has a much higher bioload than a typical 8" fish. Add to this the fact that goldfish produce a large quantity of nitrogen, and the bioload goes even higher. I personally would not keep a fish this size in anything smaller than a 55g, simply because of how quickly the water could foul (filtration will reduce the ammonia to nitrites and the nitrites to nitrates, but you'll still have a buildup of nitrates in the tank.

Well thank you for correcting me. I've owned fancy goldfish before but have scarcely seen and never owned any China Dolls.

As for tank size I do understand that Goldfish have a high bio-load and are considered 'thick' fish mainly because Goldies do not have a stomach so whatever they eat is passed through quite quickly.

Good to hear from someone more knowledgable in goldies than I.
 
JustKeepSwimming
  • #27
Beautiful fish. You got some good advice here. Yeah, you'll have to upgrade.

You might have more luck looking for "Siamese Doll Goldfish".
 
sirdarksol
  • #28
Well thank you for correcting me. I've owned fancy goldfish before but have scarcely seen and never owned any China Dolls.

As for tank size I do understand that Goldfish have a high bio-load and are considered 'thick' fish mainly because Goldies do not have a stomach so whatever they eat is passed through quite quickly.

Good to hear from someone more knowledgable in goldies than I.

I'm not necessarily more knowledgeable about goldies. I'm just pretty well versed in this aspect of them.

And I really don't know about the China dolls. Like I said, I'm not saying you're wrong, just that it seems to be something that aquarists are still figuring out.
 
afishpond
  • #29
nice fish looks like you got the help you need.
 

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