We work together only with one farm in Indonesia: the Samudra Koifarm. First because this farm is very clean and second because Samudra breeds very good quality koi.That's why we can only speak for this farm.
In general, there are koi in Indonesia as well as in Japan in every breed that have great potential, and there are koi that are left behind in the first few weeks. This is the breeder's part: the selection.
The koi we get from our Koifarm are the ones with the best potential, but even here, after a few weeks, you can see that there are some of them which grow extremely and there are also some that do not grow so fast.
The koi that we get from Indonesia have a huge size for their age. Of course, this is partly due to the predisposition just mentioned, but also because the fish swim there at very high temperatures the whole year.
We had a long talk with our chief official veterinarian, who originally comes from the fishing industry and she said that it is very normal for a carp fish to grow at a constant high water temperature about 1-1.5cm per week in the first months. This is simply because the metabolism is working at a high level at constant temperatures of 26-28°C. If feeding is still appropriate, then it is perfectly normal that the fish at 6 months can quickly have a size of 35+cm. This has nothing to do with fattening, but simply with the biology and metabolism of Koi.
And the constant high temperatures together with the fast working metabolism are also the reason why we can often determine the gender of the koi in the first months.
In response to the recurring question of how the animals will continue to grow at our temperatures, we can say from our one-year experience with them that they are developing very well. There are of course a few that grow more slowly, but as a result we can say that growing here in our inside tanks with 16-26 ° C (depending on the season) averaged 3-3.5cm in one month. We can be very satisfied with that because we can only feed them in the sales season once a day.
Many customers who have bought Aragoke from us report that the development is more than satisfying.
Finally some words about the 'big koi' we saw when we visited the Koifarm:
Usually the koi that reach the 70cm mark (often younger then 2 years) are sold there immediately, because in Indonesia they don't have the customers for larger koi. So it is common practice not to keep fish longer than 60 or 70cm in the mudponds. That's why we saw only a very few of them.
The Oyagoi are usually not shown to anyone and kept in secure concrete ponds. This is simply because very often the Oyagoi are stolen from the natural ponds or basins. We were allowed to see a few of them: Doitsu Showa and Gosanke. The fishes had an approximate age of 3 years with sizes of 70-80cm. There was a female Sanke with her Kohaku daughter, who even passed her mother by 5cm. Unfortunately it was forbidden to take pictures because the location of the Oyagoi could be detected by publishing these photos ...
Of course we had many thoughts about the sensitivity of Indonesian koi during our witerperiods at the beginning. It was important for us to talk to people who have a neutral scientific point of view about this topic. So we talked to the chief of our veterinarian office, because she is really experienced in the topic of carp biology. She argued just as we thought:
A Koi belongs to the genus of Cyprinus Carpio. This means that he is a poikilotherm animal. This biological quality can not be lost by breeding in tropical temperatures within 50 years of koi breeding! This means that the koi of course could get problems if the temperature is swinging too fast because it tries to adjust the body temperature to the outside temperature. However, if that happens in the usual slow steps, then this is no problem for a koi bred in Indonesia, as it is for the Japanese koi.
Incidentally, the japanese koi have never experienced a winterperiod too. They are taken from the Mudponds before the beginning of the cold season and taken to the glasshouses.
First every import of koi brings a risk which must be limited by every responsible importer with a proper quarantine!
We personally visited the Samudra Koifarm and have to say that they work properly and safely. If a mudpond is drained, it is always disinfected with quicklime and dried for weeks.
Many of the mudponds are leased, which means that after about 3 years of pond farming a pond becomes e.g. a cornfield again. Water-specific bacteria or viruses have no way of surviving in the soil in the long term. A method that would be of great advantage in any fishing industry!
Before the koi leave the Samudra Koifarm they are separated in various quarantine tanks.
After about 2 weeks our fish are sent to our export company in Jakarta. Hygiene is very important there. Each quarantine tank is completely disinfected each time one change of stock is changing.
KHV tests are made by the national laboratory in Jakarta of each variety of the koi which will be exported.
Depending on their stability and health condition the fish stay in quarantine for about 2 weeks.
After import we quarantine the koi again and have our own KHV tests here in Germany ...
We have to say after our one year experience with these koi from the Samudra Koifarm that they have an extremely good immune system! We were also unable to detect resistance in bacterial terms. If a koi had a slight infection from a damaged scal we usually don't have to treat it, because they have a skill of self-healing that we have almost never seen before.
In general, very cheerful, healthy and friendly and tame koi, which apparently did not have to make any bad experiences with humans.