The differences
between male and
female koi
The differences between male
and female koi
The differences between the
sexes become more apparent
as they age, particularly so in
the spawning season. Male koi
are slender, compact and
torpedo-like in appearance, with
very trim lines and smooth body
contours. They also show
behavior that is particular to
male koi and is particularly
noticeable when all male koi are
segregated into a single tank.
Male koi tend to dart around
energetically, with sharp turns of
speed, showing real 'attitude'
and a skittish character. They
are less trusting than the
opposite sex and this shy
temperament is all the more
apparent at feeding time when
they will take considerably
longer than females to feed at
the surface.
The key distinguishing physical
feature that male koi possess
develop in late spring as they
come into breeding condition.
Often mistaken for white spot,
breeding tubercles appear on
the head, flanks and tail of
mature male brood fish. To the
touch, these tubercles make the
typically slippery koi feel 'as
Rough as sand paper' giving them better purchase for when they drive and push against gravid
females in an attempt to expel their eggs. In darker koi, white tubercles will be clearly visible but
on paler or metallic koi, tubercles may only be evident to the touch.
Females on the other hand, do not develop tubercles nor will they retain the sleek lines of a male
as the breeding season approaches. Eggs that develop in the ovaries will swell, leading to an
increase in volume to the abdomen. In addition, female koi tend to behave in a less timid manner
to a tank full of males, feeding voraciously as soon as the food hits the water. Whether these
characteristics are as well defined and identifiable in a pond of mixed koi is debatable, but males
are still less likely to be the first to feed of the surface.
Pennsylvania Alabama
Florida Maine Maryland
New York Ohio California
When the water temperature is 60 degrees or above males create sperm .  Which can be observed by
applying finger and thumb either side of the vent. A female will show a swollen abdomen and a pink and
fleshy protruding vent.

Koi......Ornamental and great for algae control. These are one of the most beautiful fish. They come in
various bright colors. As a result they can always be seen in your pond. They grow up to 24 inches. These
fish are great algae eaters.
Watch your Koi as they follow your
mouse hoping you will feed them by
clicking the surface of the water.