Senior Member
Sorry for the late response....some people have to work to make a living.Junichi-san, I have not heard or read about thick skin vs thin skin and how this affects their appearance and future growth. Do you think you can elaborate on this? One thing I noticed is that Kiiroogaru has very thick skin and not a lot of luster. How do you think this will affect her appearance and growth?
Senior Member
Originally Posted by Jeff Speck
Wow Jeff, now I know why you sold the "yellow" koi. The koi that you are keeping look awesome! Good white and good growth. Tejima looks very nice!
Senior Member
Junichi-san, clearly in this "female" game, we as hobbyists have to be able to accurately sex koi (and not take dealers' words for it because they are known to be wrong). From personal communication and literature, I heard that breeders are very accurate at sexing koi. In fact, they can accurately sex koi at 8-10" in length. By the time the koi is 16-18" in length, then it is almost impossible to get the sex wrong. Is this correct?, I see..
often we can figure it out in a second by just touching fish.
If I may take this opportunity to refresh on the art of sexing koi, here is what I have learned (and please correct or add any comments you may have):
1. Young koi at tosai and ake nisai - males have pointier pectoral fins and leading rays are thicker. By the spring of their ake nisai (before they turn nisai), some males may have milt and their vents are starting to develop into either male or female vents. The pectoral fins and gill plates may have a fine sandpaper feel.
2. At nisai (end of their 2nd growing summer), the vents should be pretty obvious. Some male koi may not have the rough sandpaper feel yet since they are not sexually mature until ake sansai or sansai.
Going back to your point about "often we can figure it out in a second by just touching fish", are you talking about the fine sandpaper feel on the leading rays of the pectoral fins and the gillplates? Take these Omosako shiro for example, are you saying that at this age (nisai) and size (18") that the males should have a fine sandpaper feel and their vents look like male vents? Also, what about milt production?
The reason why I am asking is because I have a Matsunosuke (or two for that matter) that are about 17" in length and nisai. I thought that they were females, but one has a male-looking vent and I can barely feel the roughness on the two pecs but gillplates are smooth. The other male also has what appears to be a male-looking vent but no roughness at all. In fact, it feels as smooth as Kiiroogaru's and one of my sansai female gosanke. Do you think that these Matsunosuke kohaku's are males? Your opinion is much appreciated.
Senior Member
Three more things, Junichi-san. If a koi produces milt, then it's a definitive male. This means that once a koi produces milt, then it will not resort back to being a female koi in the future. Is this correct? Oftentimes I hear of case samples of male koi turning into female koi in the future or vice versa. I think that this is just a myth that should be put to rest. Koi cannot and do not change sex.
Similar to the milt example, if you can feel a fine sandpaper-like feel on a koi's pectoral fins or gillplates, then is this a definitive indication that it is a male? In other words, are there any examples that you know of where a female koi has sandpaper-like feel on their pectoral fins?
How about koi vents? Vents can be very accurate indicators of whether it is a male or female, right? Are there any examples where a koi with a male vent turns out female or vice versa? I want to know as much as I can about how to sex koi and I thank you in advance for sharing your knowledge and teaching this rook!
Senior Member
One more thing to share. Here is a case-in-point of how accurate breeders are at sexing koi. Now I know that they can be wrong once in a while, but Kiiroogaru came with a certificate. This certificate states that she is a female and was only 12" when sexed. When you look at the pix on the certificate, the pec fins and body shape looks like a male (that's why I was worried). Well, I sexed her yesterday and her gillplates and pec fins are smooth as silk and her vent indicates that she is a female. Now, how in the heck was Omosako able to accurately sex koi at this young of age? I WANT to know, Junichi-san, I WANT to know. Also, if breeders can accurate sex 12" koi, then how in the heck do they get the sex of a 17" koi wrong?!
Senior Member
My knowledge is little but from my own experience with a SU that is prone to yellow easily Hi Silk has given me the best results. That's about all I can add. Good luck with her.
Bill
Senior Member
Thank you Bill. That is what I plan on doing with her. She is in with a few other gosanke and they are currently on a staple of 1/3 Hi Silk, 1/3 Saki Hikari Growth, and 1/3 Saki Hikari Color. I also supplement them with watermellon and a daily ration of Izeki Paste Food mixed with Billion Pro, Chiton, and Magic Powder (some sort of a clay product). I have had very good growth result with this combo, so will see how she will respond to this diet. Kiiroogaru is my three year project and I will continue to update all of you on her development. I want to know more about this yellow skin that is prevalent on Omosako shiros.
Senior Member
Ahhh, Lam-san. those are a lot of questions, beyond my English ability to explain quickly
Senior Member
Speaking strictly with the SU in mind,I'd stay as far away from foods that contain ingredients that specifically target color as you can. Hi Silk does a stellar job of doing just that.
Bill
Senior Member
Lam-san, As you know, once a 50cm/20" was a size for GC and a 60cm/24" was a jumbo size. Nowadays, that is a normal Nisai size for gosanke, and in fact there are 50cm-60cm+ Jumbo tosai (ake nisai ) which is not extremely rare any more.Sorry for the late response....some people have to work to make a living.
In these days, average Gosanke with a certain background (keito) can grow to 70-75cm (28-30"), or at least they have the genetics to grow, which can be considered as a large size ingeneral. and it does not matter if Gosanke have a thick skin or a thin skin. Instead of just a large but "Jumbo" gosanke tends to have a thick skin which makes a fukurin in many cases...
some breeders & hobbyists guess that a thin skin will not be able to hold an extra large body so it should be a thick skin type for Jumbo fish...
Also, these are not a definite but a tendency......
Thin skin type : white skin color almost all the time. shows its beauty in earlier age. won't makes fukurin.
Thick skin type : yellow skin color when young and will turn to white as koi mature (female) by sansai /yonsai. takes longer time to bloom. will males fukurin.
p.s.) Omosako do love yellow ones when their SU are young.
Senior Member
[QUOTE=Lam Nguyen;1724545]Junichi-san, clearly in this "female" game, we as hobbyists have to be able to accurately sex koi (and not take dealers' words for it because they are known to be wrong). From personal communication and literature, I heard that breeders are very accurate at sexing koi. In fact, they can accurately sex koi at 8-10" in length. By the time the koi is 16-18" in length, then it is almost impossible to get the sex wrong. Is this correct?
When new born tosai pull up from mud ponds by Sept, they are most likely 6"+/- in length. we can guesstimate a gender by "smell" of color tone, size, kiwa, vent, and prettiness, etc but these are still a sort of fortune-telling in most cases. When once they grow by 8-10" in a green house of breeder by the end of the year or the early spring of the following year, a breeder can sex, say 90% so that a herd of selected possible female are being grown continuously in a heated pond until late spring. By the time the tosai ( ake nisai) is 14-16" in length as Jumbo tosai at late spring, then yes, it is almost impossible to get the sex wrong, although there are still few that are not 100% certain. but these not 100% certain ones are being eliminated in the preliminaries of nisai tategoi senbetsu so that there is (almost) no chance to be in a mud pond during summer time.
If I may take this opportunity to refresh on the art of sexing koi, here is what I have learned (and please correct or add any comments you may have):
1. Young koi at tosai and ake nisai - males have pointier pectoral fins and leading rays are thicker. By the spring of their ake nisai (before they turn nisai), some males may have milt and their vents are starting to develop into either male or female vents. The pectoral fins and gill plates may have a fine sandpaper feel.
In addition, male tends to have thick pectoral fins and female tends to have thin pectoral fins. also, male' pec fins are wider and female' pec fins are relatively narrow.
2. At nisai (end of their 2nd growing summer), the vents should be pretty obvious. Some male koi may not have the rough sandpaper feel yet since they are not sexually mature until ake sansai or sansai.
It depends on size. as you know, there are many 5-6" imported "bonsai" koi even nisai..... When once they grow to a certain size, say 10-12", male are sexually grow much faster so that you don't need to wait until ake sansai or sansai. In fact, even one year old male can use as for oyagoi.
Going back to your point about "often we can figure it out in a second by just touching fish", are you talking about the fine sandpaper feel on the leading rays of the pectoral fins and the gillplates? Take these Omosako shiro for example, are you saying that at this age (nisai) and size (18") that the males should have a fine sandpaper feel and their vents look like male vents? Also, what about milt production?
Yes, generally speaking, those Omosako SU at nisai age and size 18", you can feel the touch of the sandpaper not only the leading rays of pec fins and the gill plates but also often almost all over the body (lol), and male show its vent shape clearly, milt production as well..... so, there is almost no way to miss, although there are few exception.
The reason why I am asking is because I have a Matsunosuke (or two for that matter) that are about 17" in length and nisai. I thought that they were females, but one has a male-looking vent and I can barely feel the roughness on the two pecs but gillplates are smooth. The other male also has what appears to be a male-looking vent but no roughness at all. In fact, it feels as smooth as Kiiroogaru's and one of my sansai female gosanke. Do you think that these Matsunosuke kohaku's are males? Your opinion is much appreciated.[/QUOTE]
a male-looking vent shape dominates over the roughness on the pecs and gill plates at this time of the year. the touch of the roughness will increase in spring seasonally.
Senior Member
Junichi-san, I thank you so much for taking your time to share your knowledge. In terms of thick vs thin skin, I would think that koi with thin skin is more preferred, but your explanation really makes sense. IMO, Kiiroogaru has really thick skin and I suspect that she will have very nice fukurin some day. Will see how she looks 3 years down the road. In the mean time, I will do my best to continue to learn so that I can provide the best environment to bring out the best in her.
Regarding koi sex, I find your post very interesting. This means that it's very difficult, unless you get a certified or confirmed female, to get a female ake nisai or younger koi. The reasoning is because the females are kept to grow on and breeders are very good at sexing koi. I will anesthesize a few of my koi, take pixs of their vents and pectoral fins, and post soon to see if we can sex these koi online. Thanks again, Junichi-san.
I am just curious, do you know what Omosako feed their koi? Bill brought up a very good point about staying away from color food for shiros. However, I spoke to a couple of dealers/hobbyists and they said that it doesn't matter what you feed shiros as long as the shiros are of excellent quality. I know that Omosako probably makes their own food. Do you know how their food differs from the gosanke breeders'?
DIY Savant
Very interesting Guys, please keep it going.
pm'str
To me the head looks twinged to the side.
a tad crooked.
Ephesians 2:8-9
faith is a gift, not a personal talent.
Supporting Member
Junichi, thank you for your explanations, very interesting post.
Lam, great idea to take vent pics.
Supporting Member
Lol, well it may be a male and the head may be sideways, but if you look closely it's actually a fake fish I made from spare packing materials. Not bad, huh?
pm'str
wow, gotta show me how that is done!Lol, well it may be a male and the head may be sideways, but if you look closely it's actually a fake fish I made from spare packing materials. Not bad, huh?
Ephesians 2:8-9
faith is a gift, not a personal talent.
Senior Member
Lam-san, How many koi do we have in our pond(s) and how many koi do we usually see/touch/play at other places like dealers, friends, shows etc in a year? a breeder on the other hand if he breeds 10 pairs for instance, he will see about 2,000,000 - 5,000,000 fry carefully, and then more or less 20,000 tosai eventually within just a half year LOL. we as ordinary hobbyists can not compared with well-trained keen eyes of the pro.
I have never asked what Omosako feed their SU....that's interesting. One thing for sure is that they don't need color food for the SU which is relatively economical.
In conclusion, it does not matter to feed color food to SU's skin condition during growing season unless you feed only color food throughout the year .... because heavily feeding koi in growing season are not pretty as koi in autumn/early winter season anyway. young SU in mud ponds during summer are yellowish without solid sumi on surface as if a white radish.
Beside, we don't know why but there is an interesting practical theory by hobbyists that sumi become more darker by feeding color food.there are many things that we don't know about a mechanism of sumi, although a research laboratory of the ministry of agriculture, forestry and fisheries in Niigata has been studying about nishikigoi.
Senior Member
Well, yes in general again. I have never heard that a koi with a male vent turns out female shape vent or vice versa, but once I experienced strange thing about vent shape of 30 nisai Omosako SU at a local dealer with my friend. one of local dealer got about 30 pcs of only 4-5" small tosai from Omosako and then the fish were placed into a selling area but could not sell because the price was set too high for the size. eventually the dealer removed the SU tosai to a growing pond of his store back yard in an employee only area.Three more things, Junichi-san. If a koi produces milt, then it's a definitive male. This means that once a koi produces milt, then it will not resort back to being a female koi in the future. Is this correct? Oftentimes I hear of case samples of male koi turning into female koi in the future or vice versa. I think that this is just a myth that should be put to rest. Koi cannot and do not change sex.
Well, if a koi produces milt, then it's a definitive male at that time but male koi turning into female koi is an open fact. Believe it or not, the technique of a sex change has developed in the food industry of edible Magoi in Japan. and a sex change happens in the natural world which is caused by Endocrine disruptor http://en.wikipedia.org/wiki/Endocrine_disruptor / Estrogen http://en.wikipedia.org/wiki/Estrogen
Similar to the milt example, if you can feel a fine sandpaper-like feel on a koi's pectoral fins or gillplates, then is this a definitive indication that it is a male? In other words, are there any examples that you know of where a female koi has sandpaper-like feel on their pectoral fins?
Well, yes in a general situation but I was surprised when I touched my female oyagoi after she spawn because she had "Zara", which is called in Japanese, = sandpaper-like roughness feel on all over her body.:
How about koi vents? Vents can be very accurate indicators of whether it is a male or female, right? Are there any examples where a koi with a male vent turns out female or vice versa? I want to know as much as I can about how to sex koi and I thank you in advance for sharing your knowledge and teaching this rook!:D:
Several months later, we pull up all the SU from the pond which was totally green water in late summer. It was easy to feel "Zara" but the vent shape of almost all the fish had a female shape !!? No way....this can't be happened??
...........we could not believe our eyes.
DIY Savant
The vent shape is interesting. You can sex newly hatched chicks or pigeons from the vent shape.
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