How Long Should Aquarium Lights Be On?

How Long Should Aquarium Lights Be On?

Every aquarist should be concerned about the health of aquarium plants and fish. Aquarium lights play a vital role in the health of aquarium life whether they are plants or fish. But the question is how long should aquarium lights be on? Well it depends on various factors, and we are going to discuss them all in this post:

How Long Should Aquarium Lights Be On?

Aquarium lights have multiple purposes. For instance, you want to see your fishes, you want to grow plants or you want a natural environment for your fishes. For freshwater aquariums, the lights should be on for 8 to 10 hours maximum, but for saltwater, aquarium lights should be on for 9 to 11 hours per day.

Types Of Fishes:

As freshwater fishes came from rivers and lakes, they used to live in bright lights. So keeping your aquarium lights on for 12 hours for freshwater fishes is an appropriate option. Whereas in the case of coldwater fishes, you don’t need bright lights for 12 hours. Keeping your aquarium lights on for 8 hours is an adequate option for coldwater fishes.

Plants You Are Keeping In Your Fish Tank:

Lights requirements vary from plant to plant. For instance, carpet plants (dwarf baby tears & lilaeopsis) need 12-14 hours of light for good health. For mid-ground plants (green tiger lotus & pygmy chain sword) 8 hours of light per day is adequate. In the case of background plants i.e, the Amazon sword requires low to medium light & pondweed needs high light to grow in an efficient way.

Aquarium Lights & Algae Growth:

Aquarium lights provide multiple functions because they are specially designed for aquarium water environments. The refugium-led lights increase the growth of algae. If the algae and bacteria inside the water produce quickly you need to lighten the led lights. When you turn on the aquarium lights, for more than 12 hours they will grow blue-green algae fastly.

Fish Tank Lights & Temperature:

Fish tank lights are available in many types and the most common type is fluorescent lights because it is an inexpensive and most used product. The surrounding of the aquarium is also essential due to lights producing heat and few kinds of fish that can’t survive in more warmth. So all the aquarium lights are found in different lighting capacities.

Aquarium Lights Schedule:

We can’t treat all aquarium tanks similarly. The reason is that few salts and cold water aquarium tanks required different light capacities for their plants and fishes survival. The aquarium lights schedule is very important and by using methods you will easily set up your aquarium’s climate. Setting up the timer automatically is turned off and on helps to easily adjust led lights in aquariums.

How Much Light Is Needed?

Lights of 10 to 12 hours are enough for all types of aquarium tanks in a day. Few bottom plants (Dwarf baby tears, Lilaeopsis) want 12 to 14 hours and this medium lighting is enough for them. Midground plants (Green tiger lotus, pygmy chain sword) need 8 hours of light every day. For background plants like pondweed survive in low and medium light.

Frequently Asked Question [FAQs]

1) Is It Ok To Leave Aquarium Lights On All The Time?

No, the aquarium plants also want natural lights for their life cycle. For good survival, 10 to 14 hours of light is enough every day. All aquarium plants and fishes require different light ranges.

2) Should you turn the aquarium lights off at night?

You need to fulfill the proper lights needed for aquarium plants and fish. For this purpose the 8 to 12 hours are enough and you have turned off the lights at night due to the completion of the night cycle.

3) Can aquarium lights be off for 24 hours?

The time taken for aquarium fishes and plants is 10 to 12 hours long enough for relaxation. After this time you bring to turn off the aquarium lights for photosynthesis and sleeping process.

4) Can fish survive in an aquarium without lights?

No, the fishes can’t survive in an aquarium without lights. The reason is that a few hours of light is important for the survival of fish and plants inside the tanks. Thus, for the photosynthesis process lights are essential.

5) Can fish tank lights be too bright?

The fishes inside the aquariums are different species and need different lighting. Few light fishes need low light, some need medium light and some need bright lighting. The incandescent lights produce bright light and your aquarium will be too bright.


We tell all the information in this article about the aquarium lights that provide benefits for plants and fish. Lights are good for the aquarium atmosphere and their features are beneficial for plants growth.

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