Do Fish Need Darkness To Sleep?

Do Fish Need Darkness To Sleep?

Fish do not need darkness to sleep, but lighting does affect their rest patterns. Fish may not sleep in the same way that humans do, but they still need time to rest. A healthy day-night cycle establishes a perfect environment for both nocturnal and diurnal fish in an aquarium. So we recommend consulting a professional fishkeeper to know more about your fish resting or sleeping patterns. This will make you understand better the day-night cycle your fish requires. 

Lighting Requirements For Your Fish

Before establishing a day-night cycle, make sure to check the care guides for your fish species; as mentioned before, each fish has different needs. Moreover, lighting requirements vary by tank size. The best way to know what type of lighting you should use is to find out the natural habitat of your specific breed of fish so that you can mimic this with artificial lights if necessary.  

A general formula is to provide them with 12 hours of light and 12 hours of darkness. Both lighting and darkness are essential for fish to make them comfortable in their natural environment. For instance, you may observe the loss of color in goldfish if it is deprived of light for a certain period. At the same time, most aquarists have cited lethargy, illness, inability to rest, and loss of appetite in their fish if kept without needed lighting conditions. 

Natural Light Or Artificial Light?

It is recommended to provide as much natural lighting as possible because these creatures are susceptible to changes. Artificial lighting may disrupt their sleeping patterns. So what should you do if your house doesn’t get much sunlight during the daytime for an aquarium? Well, you could keep a low voltage blue or pink fluorescent tube to simulate the natural light cycle.

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If you choose to use artificial lighting, it is crucial that the light be low voltage and not too close to the fish. The lights also need timers to turn on and off at regular intervals to establish the proper day-night cycle. If possible, put your aquarium in an area of indirect sunlight during the day to maintain the water temperature. 

Fish can be kept under artificial light for an extended period without any adverse effects on their health or behavior. However, more natural light will help fish get better quality sleep since they are naturally drawn towards sunlight instead of artificial sources of light such as fluorescent bulbs.


If you know your fish’s resting or sleeping patterns, then knowing what kind of light they require will be easier as well. Some species are more active during the daytime hours than others. That is why its important to take that into consideration when picking out the type of light you want them under at night time. In addition to providing adequate illumination during the day, consider using soft lights when it’s dark outside. 

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