I read the below post, over on the unmoderated
newsgroup. It is certainly interesting, and since
this newsgroup is very quiet, perhaps someone here
will enjoy reading it.
I'm wishing a Happy New Year to you all.
On Thursday, November 20, 1997 10:00:00 AM UTC+2, brett rowley wrote:
> In <19971120041...@ladder02.news.aol.com
> (Ltbolt01) writes:
> >Could someone please tell me how to determine the Gender (sex) of Koi?
> >i have ten of them and i am curious as to which is which, and if i
> have both
> > sex's so i can breed them.
> Well, out of ten individuals, chances are you have both sexes present.
> Koi will usually develop and show secondary sex characterisics during
> the spring of thier second or third year. Females will usually be
> plumper than males and have very smooth skin. Males will normally be
> more slender and thier skin will become rough. Especially the head and
> fins of males will feel similar to sandpaper as the water warms in the
> spring. This is from protuberances common to the cyprinid (and some
> other families of fishes)family called "nuptial tubercles". Some male
> cyprinids, such as fathead minnows have tubercles that are very
> pronounced, resembling horns on the face. Hence when they are ready to
> spawn, they are "horny".
> Sexually mature koi that are in spawning condition can be "milked" to
> see if they are producing milt or eggs. This exercise is better left
> to somebody very familiar with the procedure as it is easy to damage
> the internal organs of the koi if they are squeezed too hard or in the
> wrong place.
> Koi will be stimulated to spawn by a combination of environmental
> factors. They must undergo a chilling period of winter, then a gradual
> warming period. After a certain amount of warmup and water temps of 59
> degrees F or more, they can spawn. Other stimulating factors includes
> a sudden increase in water level or improvement of water quality,
> females exposed to males (especially if they have been kept apart all
> year), a full moon during a warming period, the presence of suitable
> spawning substrate, and perhaps many other factors. If the koi are
> near to spawning condition, they can be artificially stimulated to
> spawn through the use of some hormones. Some of these commonly found
> on fish hatcheries are HCG (Human or Horse Chorionic Gonadotropin),
> LHrHa (Lutenizing Hormone releasing Hormone analogue), or carp
> pituitary extract.
> In most instances, if the water is good and both sexes are present, koi
> don't need much stimulation to spawn. They will go at it early in the
> morning with vigor and enthusiasm. As soon as spawning is nearing an
> end, they will immediatly begin to eat up all the recently laid eggs.
> The use of substrates such as air conditioner filters, bus seat
> stuffing, hyacinth roots, spanish moss, etc. helps to protect the eggs
> and the substrate can be moved to a hatching container away from hungry
> Rearing is the toughest part of trying to breed koi. The young koi are
> very specific as to water quality and diet. To get any chance of
> having a good baby appear from a spawning, many of them need to live.
> We will usually feed the newly hatched larvea a mix of very hard boiled
> egg yolk and powdered milk for the first three days. Then the young
> koi are moved into especially prepared and fertilized rearing ponds
> that have a lot of zooplankton, especially rotifers for them to eat.
> Usually stocking about 100,000 to 250,000 per acre of rearing pond
> (about 1/2 to 1 acre of rearing pond space per one female's worth of
> fry). If everything goes well, and the breeding stock is of the
> highest quality available (good ones are costly, $10,000+ per fish), a
> dozen or so tategoi might result, the rest running the gamut from low
> grade koi down to fish bait. Getting a good baby is like hitting the
> lotto. To do so, you must either be very lucky, or buy enough tickets
> to garauntee a hit (make enough of the babies live that the few good
> ones are in the batch). I used about 15 acres of ponds this year for
> rearing purposes. There is a lot more to do after the young are in the
> special rearing ponds, such as feeding, fertilization, applying diesel
> oil to the surface every couple of days, etc. etc.
> There are a few good books on fish breeding applicable to koi. A
> recent publication from Israel is pretty good, if very technical. My
> best cookbook doesn't even mention koi, but is a text for use in third
> world countries for growing carp to eat. It is called "A hatchery
> Manual for the Chinese, Common, and Major Indian Carps" by Jingrin and
> Pullin, published by ICLARM (International Center for Living Aquatic
> Resource Management) in The Phillipines. Available at any college
> bookstore where there is a fish culture program or through The American
> Fisheries Society.
> Sorry for the length, a very involved subject,
> Brett Rolwey
> Fisheries Biologist
> Brett's Fish Farm
> Liverpool, Texas
Louis Fourie.Hi Brett
I would like to know why the diesel or oil on the water and hoe do you feed
For me yellow egg yokes work, but even better is growth food put dry in a
coffee grinder or juicer to make it very fine