Aquariums need light for illumination and viewing the tank inhabitants’ behavior. Aquarium lights also help the fish regulate their eating and sleeping habits. They even help the aquarium plants perform photosynthesis. Insufficient lighting adversely impacts the growth of fish and plants.
Let’s now discuss the importance of light for aquariums, fish, and plants in more detail.
Why Do Aquariums Need Light?
Aquarists use lights to enhance an aquarium’s beauty.
However, light plays a more prominent role than simply illuminating the tank for viewing pleasure.
Light helps in maintaining the biological equilibrium in an aquarium.
Besides, light is essential for the healthy growth of the tank inhabitants and aquarium plants.
Aquariums need light to grow plants and other organisms that live in the water.
The amount of light needed depends on the type of inhabitant or plant you want to keep in the aquarium.
So, let’s now understand the role of light for fish and aquarium plants.
Why Do Aquarium Fish Need Light?

Light has a profound effect on the way fish function in an aquarium. It plays a vital role in mimicking the natural habitat of fish.
When aquarium fish get an environment that closely replicates their natural habitat, they tend to feel relaxed and at home.
Another advantage of light is that fish respond to the same circadian rhythm as most other life on earth.
So it’s crucial that fish have a proper day and night cycle for optimum health and well-being.
Light helps the fish to distinguish between day and night, thereby regulating their eating and sleeping habits.
Besides, sufficient lighting also helps the fish to find food, interact with other tank mates, and swim freely without the risk of getting injured by dashing on tank walls or aquarium decorations.
Moreover, light enhances the colors of fish.
It also makes it easier to spot potential problems, especially if your fish suffers from any illness.
As fish are generally more active and alert in bright light, it’s essential to have sufficient overhead lighting in the aquarium.
A minimum of 8 hours of light per day is recommended in the case of a fish-only aquarium.
However, if you have a planted tank, the lighting requirement may increase up to 10 to 12 hours/day, depending upon the type of aquarium plant.
Adequate lighting is essential as insufficient lighting hampers the immune system of fish, making them susceptible to diseases.
Fish also become lethargic and even lose their appetite.
Moreover, some fish like goldfish tend to lose color if the light is insufficient.
Although aquarium fish need adequate light during the day, darkness at night is equally vital for the fish to rest and sleep peacefully.
So it’s crucial that you maintain a proper balance of light and darkness for the overall development of your fish.
Why Do Aquarium Plants Need Light?

Light is life for aquatic plants. Without sufficient light, aquarium plants simply can’t grow.
They need light to perform the photosynthesis process for their healthy growth.
All plants use light to prepare food through the photosynthesis process.
In the presence of sufficient lighting, the chlorophyll pigment in the plant’s leaves gets activated.
Proper lighting enables the aquarium plants to absorb carbon dioxide that fish and other tank inhabitants exhale.
Thus aquarium plants produce their food with the help of light and carbon dioxide from the tank water.
Since aquarium plants can’t perform photosynthesis without light, they will eventually perish without sufficient lighting.
Apart from light, aquarium plants need to have proper fertilizers and carbon dioxide dosage to thrive.
Different aquarium plants have varied lighting requirements.
Some need intense lighting, while others can easily thrive in medium to low lighting.
So it’s important to understand the lighting requirement of your plant and accordingly decide the duration for which the light needs to be kept on in your planted tank.
You should also figure out the best light placement so that every plant in the aquarium gets sufficient light.
Generally, 8 to 10 hours of lighting is ideal for aquarium plants.
However, if you have plants that need intense lighting, you can keep the lights on for around 12 hours/day.
While deciding on the lighting duration, you must remember that plants need a proper day/night cycle to provide a consistent photoperiod for optimum growth.
So switching off the aquarium lighting for the rest of 12 hours is equally important.
It’s also advisable to have a timer installed to switch the lights on and off as needed.
Alright! Now that you know the importance of adequate lighting for fish and aquarium plants, you may wonder which color light is more beneficial.
Should You Use White Light Or Blue Light In An Aquarium?
Many aquarists prefer white and blue color lights because of their numerous benefits.
However, both lights have their pros and cons. So you need to choose the one that best suits your aquarium needs.
Why Should You Use White Light For An Aquarium?
Aquarists use white light as it gives a natural look to their aquariums.
Besides, some shades of white color are brighter and hence illuminate the tank better.
Aquarists can easily watch the behavior of their tank inhabitants in white light.
White light also causes less green coloration of the water and makes it easy to keep the tank clean.
Although white light is good for fish-only aquariums, the same can’t be said for planted tanks.
White lights are not suitable for aquarium plants as they lack the necessary red and blue spectrum needed for the optimal growth of plants.
Moreover, algae grow the best under white light. So algae bloom in the aquarium is high if white light stays on for longer.
Why Should You Use Blue Light For An Aquarium?
Blue light is widely used in aquariums as it provides a moonlight effect that helps the fish calm down.
Besides, it also helps to mark the transition between dawn and dusk.
Another benefit of blue light is that it doesn’t contribute to algae proliferation in the aquarium.
Lighting usually increases the water temperature, proving fatal to fish. But blue light doesn’t raise the water temperature.
If you have a community tank with diurnal and nocturnal fish, blue light is the best option.
Blue light allows the diurnal fish to sleep at night while the nocturnal fish venture out in search of food and carry on their routine activities.
Blue light also encourages more physical activity in fish, thereby improving their health.
If you have multiple fish with vibrant colors, blue light helps stimulate the blue, red, and green shades of color, thus making the aquarium look more appealing.
Moreover, if you have a sick fish, blue light allows you to monitor the health of the sick fish and spot any potential problems that arise during the night.
Blue light is also beneficial in planted tanks, as it helps to stimulate the growth of aquatic plants.
Blue light helps in the photosynthesis process, thus making the aquarium plants healthy.
Plants use a specific kind of blue light called Actinic Blue for vegetative growth.
Plants that grow under actinic blue light tend to grow very bushy and leafy.
What Color Light Is Good For Aquariums? White Or Blue?
There is no right or wrong choice between white and blue light. Both lights have their pros and cons.
White light tends to illuminate the tank better, whereas blue light has a calming effect on the fish and helps in the optimum growth of plants.
It all depends on the kind of aquarium you have set up. If you have a fish-only aquarium, white light works well.
However, if you have a community tank with different fish species or a planted tank, blue light is a better choice.
You need to choose the lighting considering the factors that best suit your aquarium fish and plants.