Koi Sexes

Today, on my way back from Port Dickson, I was thinking about My First Blog. Need to go to Port Dickson because my son (age 8 years old) wanted to play and swim at the beach, so our family went for a picnic. Port Dickson is situated in Negeri Sembilan (one of the state in Malaysia) and facing the Straits of Malacca.

My First Blog is created for my Blog Assignment from the Management Information Systems class (where I am pursuing my Master from University Utara Malaysia, one of the leading universities in Malaysia). After creating the blog, then came the challenge what am I going to write in the post. After a few days, I think I would share about one of my hobbies that are keeping my koi.

Koi fish is quite expensive here, so I keep the cheaper version (the local breed koi). It started ten years ago, where I have 6 feet by 3 feet tank. I can still remember during those days where some of the fishes will get stolen and a few die during the haze spell which occurred a few years back.

Now, I’m bit careful after the entire incident. When my last three koi (started from seven) grew about two feet, the tank was not enough room for it’s to swim. Therefore I build ten feet by three feet with three feet depth pond and also with shade (you can see at My Fish photo slideshow). After the pond has completed, I bought ten two and half inches koi, which now have grow one foot.

I enjoy seeing its swim in the pond. It’s not easy to know the koi sexes, here are some clues.

How to tell the difference between male and female Koi.

Many people wonder if their Kerry is a Kelly or if their Lola is a Larry because they are unable to tell if their Koi is a male or if it is a female. There are a couple subtle differences which will be explained. These are general facts that have been figured out over the years. Study your Koi greatly before you determine it to be a he or a she, many Koi have be mistaken for the opposite sex over the years!

The Fins

They are a Koi's means for propulsion. Female and Male Koi have different looking fins. Female fins tend to be larger, but will have less color. Female fins will have a rounded edge and will be opaque.

Male fins will have a pointy edge and will have a solid color look to them.

Body Conformation

Male and female Koi have different body conformations. Male Koi will be long and skinny, like a cigar, female Koi will look more like a blimp. Female Koi get wider than male Koi because they carry tons of eggs. Many Koi collectors make it a point to only have female Koi in their ponds, since the large and wide body displays patterns much better. That is why most of the award winning Koi at shows are female.

Female Koi grow larger than male Koi.

This is the reason why:

When the Japanese breed Koi, they pair a group of males to one female. They do this to get a wide variety of genetics, boosted immunities, and a nice selection of colors/patterns. Now, if you are going to breed one female with a bunch of large males, she is going to get pretty beaten up. This is not good, since a nice breeding female can cost more than a decent house. In order to prevent the female breeders from getting beaten up, they pair a large female with a bunch of smaller males. Since the process is repeated every generation, the males will always be smaller than the females.

Telling the Difference:

It is much easier to tell the differences between sexes when Koi get larger and older. When they reach sexual maturity, at around 2 years of age and around 12" of length, the females will fill up with eggs. This will give them the blimp look. When Koi are larger, it is easier to tell if their fins are pointed or rounded and if they are clear or opaque.