Should Aquarium Lights Be Left on?

It is important to have the correct lighting for the right amount of time per day, or it can cause fish stress. Aquarium lighting is meant to replicate their natural habitat. If light is left on all the time, with no "night," they don't have any other way to normalize their behavior.

  1. The Effects of Improper or Insufficient Light

    • Insufficient light can cause brown algae to grow in your tank.

      Brown algae can start to grow in layers in your aquarium due to insufficient light. This and improper light can lead to fish stress with symptoms, such as lessened activity, dull coloration and poor growth.

    The Effects of Too Much Light

    • Using a timer is for light makes sure your fish are getting the right amount of time in the light.

      If you leave the light on all the time it will increase the growth of green algae in the tank. Using a timer is an inexpensive way to make sure the lights are turned on and off at the right time. Excessive light also can result in fast growth but a shorter lifespan for your fish.

    The Right Amount of Light

    • Uniform lighting is important for healthy plants.

      The right amount of time for the light to be on is between the range of 8 and 12 hours depending on the species of fish. Uniform lighting also is important for healthy plants and fish. Dark corners tend to shorten the lifespan of any plants in your tank.