The ideal natural daylight alternative for koi kept indoors

At Yoshikigoi Koi Farm, we keep large numbers of our highest quality Koi indoors (particularly over the winter period) and let them grow at temperatures of between 22 and 24 degrees, where the Koi’s colour, and especially the preservation of the pigment, is extremely important. That this is not an easy thing to achieve, in fact, that it is almost impossible, is well known to anyone who keeps their fish indoors. When I heard about the Koi Spectrum Lamps, of course I was curious to know whether we could benefit from using it indoors on the koi farm. I initially had a lamp hung above one of the smaller tanks and was very pleasantly surprised that after only two weeks the results could be seen with the fish. The yellows became deeper and the red colours also gained in intensity. After 4 to 6 weeks, I also saw that the pigment not only became vibrant, but also significantly stronger in its depth. Kiwa and Sashi also became sharper in the patterns. This made us decide to equip all our tanks in the fish house with Koi Spectrum lamps. We have now tested it extensively and are very pleased with the results. Of course, seeing is believing, but this is something that we can see clearly see actually works!

I have the koi spectrum lamp hanging above my growing tank for a few months now. The moment the lamp is switched on it starts up with minimal blue light which slowly becomes brighter and brighter, so you don't suddenly startle the fish. At present, I only have shiro utsuri and a benigoi swimming in the growing tank The red on the benegoi was already receeding before the lamp was hung above the tank, but this now seems to be gradually improving again. It is also noticeable that the sumi on the Shiro Utsuri is developing and deepening to a deep black. These lamps are definitely recommended for use above an indoor pond where natural light is limited/absent.

I have had the lamp above my growing tank for three months now and my experiences are very good. What I noticed at first is that algae started to grow on the walls of my growing tank, which was not the case before. I took part in the KoiCave Yamabuki challenge and what struck me was that the fish of the other participants kept under standard lighting generally turned very pale, while my fish stayed nice and yellow. As to the Shiro that are swimming in the same tank, the black is coming through very nicely and on the Kohaku, the red remains beautifully consistent and has not faded.

Optimal Lighting for Our Koi: Why We Choose Koi Spectrum Lamps At our facility, we have two quarantine tanks, each with a capacity of 3 cubic meters. Initially, we used standard fluorescent fixtures with LED tubes for lighting above these tanks. While functional, it quickly became apparent that this setup was not sufficient to maintain the vibrant colors of our koi. So, we began searching for a better solution. It didn’t take long before we discovered Koi Spectrum lamps. We decided to invest in one, despite the significant cost. But as the saying goes, “anything for the koi!” The results spoke for themselves: the colors of the koi were noticeably better preserved under this lighting compared to the old setup. Still, the thrifty Dutchman in me wanted to explore cheaper alternatives. That’s when we came across a round lamp reportedly used by many koi dealers in Germany. We installed this lamp above our second quarantine tank. After nearly a year, we compared the results. The conclusion? The koi under the Koi Spectrum lamp retained their colors much better than those under the more affordable lamp. The outcome: we’ve now ordered a second Koi Spectrum lamp. This once again proves the old saying: you get what you pay for. When it comes to the health and appearance of our koi, the right lighting is simply indispensable!

About six months ago, I started using the KoiSpectrum Pro1 lamps. Although I had known about them for quite some time, I was initially skeptical about their effect. That changed when I saw more and more customers achieving stunning, vibrant koi colors without any natural daylight – solely thanks to these lamps. After hearing so many positive customer experiences, I decided to take the plunge myself. Together with Paul, I installed the KoiSpectrum Pro1 lamps on all 11 of my grow-out tanks. Paul supported me in a very professional and pleasant way. He gave clear advice on the best placement and height for the lamps and even installed individual switches so that each tank can be controlled separately. The lamps now run 16 hours a day. The koi still follow a natural day-and-night rhythm through the windows in the facility, but without any direct sunlight. The difference compared to last year – when I raised tosai without lamps – is remarkable. Back then, the beni visibly degraded, whereas now it remains much richer and more stable, even in fast-growing koi. I also notice that the fish are calmer and happier thanks to the lighting and the smooth sunrise/sunset effect of the lamps. Of course, installing 11 lamps is an investment, but honestly, I should have done it a year earlier. Finally, I want to emphasize that Paul’s service is outstanding. He is reliable, keeps his word, and always thinks along, even when the issue was entirely my own fault. In short: very satisfied with both the lamps and the service. Thank you, Paul!