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Do Koi Fish Require Light at Nighttime?

Light at Night for Koi Fish San Diego, CA

Like many other aquatic and terrestrial species, koi regulate their life activities according to circadian rhythms, which are in turn regulated by periods of illumination and darkness. The Asian carp species that koi descend from live in rice paddies and other habitats where aquatic grass grows thanks to photosynthesis. In other words, koi naturally expect to get sunlight during the day. At night, koi are genetically predisposed to anticipate a combination of darkness and moonlight, although this won’t automatically put them to sleep. With this in mind, we can safely assume koi don’t need artificial lighting at night, but there’s more you should know in this regard. The friendly and knowledgeable staff at Aquatic Warehouse, a trusted provider of koi pond supplies, share a few important details about lighting for koi ponds.

Koi Need Overhead Light

Whether it’s sunlight or artificial illumination generated by lamps, koi need to be exposed to a few hours of daytime light. This is what will stimulate the aforementioned circadian rhythm. In the case of backyard ponds, the sun will take care of this even during cloudy days. Indoor ponds that don’t get any sunlight will require artificial overhead lamps, preferably modern LED lighting with programmable timing and a means to adjust intensity. Research studies show that koi will lose their color and become disoriented when they don’t get about eight hours of overhead daytime light.

Koi Need Periods of Darkness

Garden pond keepers must do their part to provide day and night cycles for koi. Eight hours of daylight and eight hours of darkness are sufficient to facilitate this cycle. Koi won’t sleep through the entire period of darkness. If they have plants to nibble on, they’ll do so at night unless this happens to coincide with their feeding schedule. Even if you keep a single koi in your pond, it will choose to sleep a few hours during the day and some at night, but it will still need a period of darkness.

Indirect Landscaping Lights Are Better

If you want to enjoy looking at your koi at night, there would be nothing wrong with installing an overhead light as long as it can be turned off around 10 or 11 at night. A better option would be to install lights in the garden sections around the pond so they don’t shine directly on the water. This provides a more attractive aesthetic and it’s closer to a moonlight effect. Needless to say, soft LED lamps will always be more suitable.

Fountain, Waterfall, & Floating Pond Lights Are Additional Options

Thanks to advanced LED technology, you can now install many kinds of lights to decorate your pond at night. Fountain lights and floating lamps in the shape of water lilies are very popular. Many of them are colorful and can be programmed to flash in various patterns reminiscent of Christmas lights. Feel free to decorate your pond with these lights, but don’t forget to turn them off about eight hours before sunrise.

From lighting and filtration to beneficial bacteria and submersible pumps, Aquatic Warehouse has all of the pond equipment necessary to maintain a healthy pond environment. Stop by our store located in Kearny Mesa, order what you need from our website and have it shipped to you, or give us a call today at 858-467-9297 if you have any questions.


Contact Information

  • Address: 5466 Complex Street Suite 204
    San Diego, CA 92123
  • Phone: (858) 467-9297
  • Email: sales@aquaticwarehouse.com
  • Working Days/Hours: Mon - Fri / 10:00 AM - 7:00 PM
    Saturday / 10:00 AM - 6:00 PM
    Sunday / 11:00 AM - 6:00 PM


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