How to Determine Koi's Age?

[DaneDad]

Just purchased six koi fish from my local garden center here on Long Island. They are approximately four inches from head to the base of their tails. They don't look stunted as their eye size is appropriate for their body size.

Can someone tell me the approximate age that they might be? I'm guessing 8 months but I really have no clue.

Is there a basic guideline for koi growth? I'm guessing if the water is warmer they will grow faster as long as they are fed several times a day

 

[koidaddy]

Just an observation with mine. Ones I purchesed from my pet store grew at a slower then lats years spawn. By alot. I have some purchased before the spawn that were 3-4" at the time. Last years spawn are much bigger, say 20%, but not as old.

 

[fishin4cars]

A four to five inch koi should be about 1 year old. most Koi breeding take palce between Late april to the end of June, there are exceptions of course but this is the norm.
Tosai = 1 year old
Nisai = 2 year old
Sansai = 3 year old
Yonsai = 4 year old

If you google koi gaes some sites say they can be told how old they are by the rings in the scales, however, this is by far not 100% accurate, Also size can not determine age either as some Koi grow at far faster rates than others. I have heard that there is someone that is working on a butterfly Koi that will only reach about 16'-20" full grown but that too is from waht I have read and cannot find any information that backs this.

 

[DaneDad]

Many of us wonder, "how old is our favorite Koi"? One way to guess at the answer is to measure how long they are, and then check the Koi Growth Charts.

However, most Koi have scales; thin, overlapping plates of bone that continue to grow throughout life. As they grow they do not increase in number, but rather increase in size. The growth of the scales is proportional to the Koi's growth, and annual marks are formed on the scales at the same time every year, along the outer edges.

So if you look at a Koi scale, it turns out that just like trees in cross-section, they have annular rings. If your Koi has lost a scale, look at it closely, even under a microscope. Then count the number of annular rings, and your Koi is at least that old, but it maybe even older. This is more accurate for younger Koi, i.e., less than 5 years old.

However, if a Koi looses a scale, and then grows it back, the new scale will not have any of the older rings. Also females may not add growth rings when they are reproducing, or grow some more after reproducing, causing 1 growth ring to look like 2.

A more accurate way to judge a Koi's age is to examine the cross-section of a fin spine, which also has annular rings. The second anal fin spine is often used. This can be done without doing permanent damage, since the fin will grow back.

The most accurate way to determine a dead Koi's age is to examine the Otolith (Williams and Bedford 1974). The Otolith is the Koi's "ear bone". Otoliths are part of Koi's vestibular apparatus, and reside in the cranial cavity. They are composed of calcium carbonate and protein. They function as sound receptors and are also used for balance and orientation.





There are 3 pairs of otoliths or ear stones in the inner ear of a Koi. The largest pair of Otoliths, the sagittae, are routinely used for aging. So Otolith is synonymous with sagitta. Again you count the number of annular rings under a microscope. White bands are formed during the spring and summer months, while darker bands are formed during winter. The Koi's age can be approximated by counting the light and dark bands as one year.

This technique has recently (5/29/2000) been successfully used by Canadian fishery researchers in Halifax to determine that ocean perch reach the age of 75 years, instead of 30 years as was previously believed.

from http://www.coloradokoi.com/koi_age.htm

 

[koiguy1969]

i cut them in half and count the rings...like a tree!..........lol..sorry, i couldnt help myself!

 

[fishin4cars]

Many of us wonder, "how old is our favorite Koi"? One way to guess at the answer is to measure how long they are, and then check the Koi Growth Charts.

However, most Koi have scales; thin, overlapping plates of bone that continue to grow throughout life. As they grow they do not increase in number, but rather increase in size. The growth of the scales is proportional to the Koi's growth, and annual marks are formed on the scales at the same time every year, along the outer edges.

So if you look at a Koi scale, it turns out that just like trees in cross-section, they have annular rings. If your Koi has lost a scale, look at it closely, even under a microscope. Then count the number of annular rings, and your Koi is at least that old, but it maybe even older. This is more accurate for younger Koi, i.e., less than 5 years old.

However, if a Koi looses a scale, and then grows it back, the new scale will not have any of the older rings. Also females may not add growth rings when they are reproducing, or grow some more after reproducing, causing 1 growth ring to look like 2.

A more accurate way to judge a Koi's age is to examine the cross-section of a fin spine, which also has annular rings. The second anal fin spine is often used. This can be done without doing permanent damage, since the fin will grow back.

The most accurate way to determine a dead Koi's age is to examine the Otolith (Williams and Bedford 1974). The Otolith is the Koi's "ear bone". Otoliths are part of Koi's vestibular apparatus, and reside in the cranial cavity. They are composed of calcium carbonate and protein. They function as sound receptors and are also used for balance and orientation.





There are 3 pairs of otoliths or ear stones in the inner ear of a Koi. The largest pair of Otoliths, the sagittae, are routinely used for aging. So Otolith is synonymous with sagitta. Again you count the number of annular rings under a microscope. White bands are formed during the spring and summer months, while darker bands are formed during winter. The Koi's age can be approximated by counting the light and dark bands as one year.

This technique has recently (5/29/2000) been successfully used by Canadian fishery researchers in Halifax to determine that ocean perch reach the age of 75 years, instead of 30 years as was previously believed.

from http://www.coloradokoi.com/koi_age.htm

I have read on multiple Koi forums that this way of aging koi has been found to be inaccurate. Koi growth rates can be directly related to water conditions, so if water conditions have dropped the fish may slow down it growth, But a heavy rain or water change can improve the water and this growth spurt will result in new rings being formed. there was a test done and if I can find it I'll link it back here but a Koi of known age was aged this way at 1 year, 2 years, all the way up until it was 10 years old, It was found at the end of ten years that the fish showed it was 14 years old when it was actually four years younger than the the scale rings showed. Which also questions if the Koi Hanako( the worlds oldest Koi) is actually accurate.

 

[DrDave]

I posted an article here some time ago aabout the worlds oldest Koi. It is in Japan and was 260 years old.

 

[fishin4cars]

http://www.flickr.com/photos/balcer17/2255019328/

I have read that the accuracy of this is in question. I'm not saying it is or isn't fact. I don't know.:lol:

 

[Giovanni Carlo Bagayas]

I think the best to tell the age is breed your own koi he he

 

[Rhonddaponda]

Just purchased six koi fish from my local garden center here on Long Island. They are approximately four inches from head to the base of their tails. They don't look stunted as their eye size is appropriate for their body size.

Can someone tell me the approximate age that they might be? I'm guessing 8 months but I really have no clue.

Is there a basic guideline for koi growth? I'm guessing if the water is warmer they will grow faster as long as they are fed several times a day

I had pairs of ,koi, shobumpkin, orf and goldfish in my pond. They spawned the first year and a number of 'pinkeens' survived. The shobumpkins were pink, grey and white straight away. The goldfish changed colour in the second year, some black and gold some white and gold and some pinky white. I still have two fish Koi shape that are still black with a kind of shimmery gold, they do a lot of jumping and are very fast, are these koi fry? Sad to say lost 4 of the big fish in the heat wave last summer, the rest are fine now. Be interested in any comments on the dark fish.