Koi in a 55 gal?

  • #1
I recently purchased 5 koi for a 55 gal tank. the salesman told me they were shubunkin, but after checking online I realized they are not. I have been doing some reading and many claim that tank size stunts growth and that the fish will suffer health issues including spinal deformities.

I have also read that they will simply adapt to the size of the tank and suffer no ill health with good filtration. So which is it? I really do like them... and the only shubunkin I've seen that compare have long bodies, dorsal fins and tails. Does anyone know which variety this is? I can't find them locally however and would be stuck with those torpedo shaped shubunkin/goldfish with the long tails.

Any advice would be appreciated! I'm trying to stick to fish that don't need heaters.
  • #2
Do they have whiskers? Kind of a fu man chu mustache? I don't know a whole lot about Koi but I feed my Oscar shubunkins sometimes. I believe Shubunkins look very much like Koi except a skinnier head and no whiskers. Either way they are both really more of a pond fish. Koi can grow to be 2-3 feet, and yes stunting them in a small tank is no good for them regardless of filter. I kept a Comet (similar to shubunkins) in a 150 for awhile but he had to go to a pond to make room. And that is the extent of my Pond fish experience.
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  • #3
yup they have the small mustache (I think I've seen it called barbels). I'm told that that feature is exclusive to koi.
  • #4
That's my understanding as well with the barbels. Like I said Koi get to be 2-3 feet and I personally feel that it is bad for them to be in too small a tank. Although they will stay smaller in size, their life span will be much reduced and other health problems can come up. Goldfish are kept in bowls but in reality they are a fairly sizable fish. That's why Goldfish always die young. (Not all I know just going for dramatic effect). Good filtration can help yes but the way it was best put to me is that you should plan for an environment that fits the adult. You need 4 times the fish length wide, 2 times the fish length deep, and 2 times the fish length tall. Give or take a bit. At 2ft. long a Koi needs 8ft X 4ft X 4ft. Just a general rule of thumb for large fish.
  • #5
there are some places that will trade small fish for big fish
we got three large goldfish that a lady traded in for guppies cuz they got too big
  • #6
Yeah, koi can only live for so long in such a small tank (I'm currently working on getting a 200 gallon for my butterfly koi, who's only four or five inches right now)
  • #7
Some koi have been raised to 4 feet in length, there is even a 150 year old Koi in a Japanese monastery that has a huge pond dedicated to their 5 in a half foot koi.

Pretty much they get big, live long and are really suited to ponds only. I would either return them or start digging.
  • #8
I agree with Jacko.

The ONLY reason fish stay smaller in tanks not big enough for them is because they DIE before they are able to grow much. They usually die of ammonia poisoning. ANYONE that knows the first thing about fish that informs you that a tank too small for a fish will be fine with good filtration, to that extent, (a 3-4 foot fish that weighs upwards of 60 pounds in a 4 foot long by 1 foot wide tank) should not keep fish and can be chalked up as a moron.

I would suggest returning the fish or start digging a pond and forking out the dough for butyl rubber lining ($9 a square yard 20 years ago when the pond in our yard was done.)
  • #9
Today it runs about 11 bucks per square yard at the box stores, you might find it cheaper at specialty stores though.
Not only do they get 3-4 feet, but they can reach more than a foot in diameter and more 14 inches tall.

Also, shubunkins get rather large and wouldn't have been suitable for that tank.

Also, a clear tank is not the best choice for the Koi, even if the tank was a mamoth tank. They would be far more stressed in that situation than other regular fish. Koi are one of the most intelligent fish out there, they have nearly the same eyesight as humans and see things more defined than fish and contain personalities that can only be a result of the refined breeding over the centuries.

They show up in history alot, there was a kingdom thingy clash in Asia when one group accidently killed a large prize Koi at the others place. Some asian sub-religions veiw them as near gods because of their long lives and intelligence. Some being called centuries old, no proof of that though.
  • #10
Some being called centuries old, no proof of that though.

Not true, there was a female koi that was 255 years old that died last year. Her age was verified scientifically, and while they may have been off by a couple of years or even a couple of decades, that still puts the fish at over two centuries.
  • #11
I am not saying there arn't any older than 200, just some of the stories that I have found have no proof. Come on, I don't think a Koi, 4 feet in length can be 500+ years old!! Dang WikI and other "specialist" sites!
Sad such a majestic creature died.
  • #12
I understand, I was just saying that there is one scientifically supported case of a koi that survived well beyond 200 years.
  • #13
Do you have any pics? Koi will keep growing regardless of the size of tank they are in so if they are koi, a pond would be best...shubunkins are more closely related to comets (the standard goldfish found in stores and sold as feeder fish) and will grow to the size of the tank. I had one goldfish that I got when I was in high school and it was still going strong until a cat got it out of my pond. I had had it 17 years...It never got more than 4-5 inches long when I had it in a tank, when I moved it to my pond it started growing again and was almost 9 inches when the cat got it. It would come up and nibble on my hands and eat pellets out of my fingers.
  • #14
Shubunkin are goldfish.
  • #15
The oldest koi I have seen records of was over 200 years. It sounds like you were sold butterfly koi which do stay smaller than regular koi but they will still quickly outgrow a 55gallon. They should be alright till spring but you need to get a pond. Get a test kit ASAP and keep your water in perfect condition and there should not be any spine damage to them in the next few months until you can get them a bigger home. You can somewhat limit their growth by not feeding a lot or a high protein food. I would suggest a wheat germ based hikarI diet.
You can use rubber but why do a pond halfway? Pond kits are really your best bet as far as cost and quality are considered. Plus kits come with everything including instructions. Email me for details, Gail at
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  • #16
Thanks Gail! As it turns out I never got around to returning them and they had already grown on me. I've been getting more and more into the idea of a pond and hey, even if I don't build one I can always find them a good home in someone elses. It kind of fits with my personality anyway to nurture them and then want to see them into the best home possible.

You mentioned wheat germ in their diet... I currently am feeding them food from almostnaturalfishfood.com What attracted me to the food is the lack of additives, preservatives and the lack of wheat. I myself am on a wheat free diet because wheat is an allergen for many people. I never thought I was, but then I got off it and experience less inflammation, more energy and even more mental acuity. I am told these are all common experiences when one sacrifices wheat.

I don't want to blindly make my fish wheat free, I just don't know what it's supposed to be doing for them and I've never heard of fish snacking on wheat in natural habitats.

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