An aquarium is not simply a glass tank with some water and fish in it, but a miniaturized eco-system that needs multiple components in order to thrive. Any successful build will therefore typically need the following mandatory components:

In this article we will take a closer look at lighting in freshwater aquariums. We'll cover everything you need to know about aquarium lighting, including the different types of lighting, how to choose the right lighting, and how to maintain it.

Proper lighting not only enhances the beauty of your aquarium but also plays a vital role in the health and well-being of your aquatic plants and animals.

What to Consider when Buying Aquarium Lights

Important! You don't need to spend a ton of money to buy an aquarium light from an expensive aquatic brand. The most important aspect is the amount of lumen and the color temperature.

If you are new to aquatics, it is good to know that there are a lot of products out there to choose from. Most products are very expensive and can be acquired cheaper if you don't specifically look in the aquatic section.

A good alternative to aquarium lighting are floodlights. In case you intend to buy lighting from a non aquatic brand make sure the product is waterproof.

It is better to buy an overpowered light (which can be dimmed) than a cheaper light meeting the requirements just so. The overpowered lights gives you more options in case you want to grow light hungry plants.

In case you are not sure what to look for please read the following.

Things to Look Out for in Aquarium Lighting

When reading and researching aquarium lighting you will find a lot of keywords. As a beginner, the only things you need to consider when buying an aquarium light are

  • Amount of light measured in lumen (lm)
  • Color Temperature

Amount of light measured in lumen (lm)

First we need to look at how many lumens a lamp has, which is the measurement of light that is being emitted from a source. The more lumens, the brighter the light.

As a comparison: Moonlight amounts to approx. 1 lumen when measured on earth, the average light in the living room is around 50 lumens and the sun at its highest point produces up to 100.000 lumens.

But how many lumens do you actually need for your aquarium? It depends on the type of plants you want to grow and how much water you have in your tank:

  • For easy plants you require between 10-20 lm per liter / 38-76 lm per gallon.
  • For medium plants you require between 20-40 lm per liter / 76-152 lm per gallon.
  • For advanced plants you require more then 40 lm per liter / 152 lm per gallon.

In addition you need to take into account the aquarium depth and the distance to the light source. Unfortunately there is no rule of thumb for this calculation, as the water conditions and color also have an effect on how much light comes through.

Here is a rough calculation for clear water:

  • 8 in / 20 cm below water only 50% of the lumens produced at the light source are left
  • 10 in / 25 cm below water only 29% of the lumens produced at the light source are left
  • 14 in / 35 cm below water only 14% of the lumens produced at the light source are left

Example: Let's say you have four LED bulbs with 9W to light your 30 gallon tank. These types bulbs usually yield around 800 lumens of light per piece. So you have 3200 lumens of light / 30 gallons, which equals 104 lumens per gallon. With this amount of light you can have medium plants close to the surface of your tank and easy plants up to 8 in (20 cm) below the water surface. Plants further below the light surface will probably have problems.

If your light doesn't specify the amount of lumen on the packaging, you can also roughly determine the lumens by looking at the amount of Watts on the packaging and taking the type of bulb into consideration:

Lumens Standard Halogen LED
450 40 W 29 W 6 W
800 60 W 42 W 9 W
1100 75 W 53 W 11 W
1600 100 W 72 W 14 W

Color Temperature

Aquarium color temperature refers to the warmth or coolness of the light in your aquarium. This is measured in Kelvin (K), which is a unit of measurement for temperature. The lower the Kelvin number, the warmer (more red) the light appears, while a higher Kelvin number will give off a cooler, bluer light.

What Color Light is Best for Aquarium Fish and Plants?

Aquarium color temperature is important because it can affect the behavior and health of your animals and plants. Different species of fish and plants have different requirements when it comes to lighting. For example, some fish are more sensitive to light and may become stressed or agitated if the color temperature is not suitable for their needs.

Plants, on the other hand, require only blue and red light to photosynthesize and grow. Without the right color temperature, they may wither or die.

Green light is not beneficial for plant health or growth. It is only used in aquariums to make green plants look even more lush and vibrant.

To achieve the perfect color temperature for your freshwater aquarium the color temperature should be between 5500 K and 7000 K. This range contains the necessary blue and red light waves to grow healthy plants. As a comparison: the sunlight has a color temperature of 5500 K.

The color temperature of your lighting can also affect the overall aesthetic of your tank.

Types of Aquarium Lights

There are three main types of aquarium lights:

  • fluorescent,
  • LED and
  • metal halide.

Metal halide lights are very expensive and need to be replaced more regularly than e.g. LED lights. Even though they do yield an excellent colorization, they're not very popular anymore due to cost.

That's also why we'll only take a closer look at the first two:

Aquarium Fluorescent lighting

Aquarium fluorescent lighting is a popular choice among aquarium hobbyists due to its affordability and effectiveness in promoting plant growth and enhancing the coloration of fish.

Attention: When the bulb / tube breaks it is important not to breathe in the dust as this can severely damage your lungs.

Benefits of Aquarium Fluorescent Lighting

One of the main benefits of aquarium fluorescent lighting is its affordability and ease of maintenance when you need to replace bulbs.

Compared to other types of aquarium lighting, such as LED or metal halide lighting, fluorescent lighting is relatively inexpensive to purchase and operate. This makes it an ideal choice for beginner hobbyists or those on a budget.

Another advantage of fluorescent lighting is its ability to promote plant growth because fluorescent bulbs emit a spectrum of light that is ideal for photosynthesis. Using fluorescent lights can also enhance the way your fish look by enhancing their colors.

Choosing the Right Fluorescent Lighting

When choosing fluorescent lighting for your aquarium, the main things to consider are the required amount of lighting for your tank and the color temperature.

You can refer to the sections above to get more information on how much light your tank needs and which color temperature is best for you.

In conclusion, Aquarium fluorescent lighting is an affordable and effective way to promote plant growth and enhance the coloration of fish in your aquarium. By choosing the right size and color temperature of bulb, you can create a visually appealing and healthy environment for your aquatic pets.

Aquarium LED Lighting

Aquarium LED lighting has become increasingly popular in recent years due its energy-efficiency, longevity, and broad color spectrum that can create stunning visual effects in your aquarium.

Benefits of Aquarium LED Lighting

One of the main benefits of aquarium LED lights is their high energy-efficiency. They consume less power than traditional aquarium lighting, which means that you can run your aquarium light for longer periods without worrying about high electricity bills. This also has a direct impact on heat reduction. Unlike traditional lighting options, LED lights do not produce as much heat, which means they won’t have an impact on the water temperature in your aquarium and therefore won't harm your fish and plants.

Another main benefit of aquarium LED lights is thir longevity. They last longer than most other light options, which means you won’t have to replace them as often. This makes them a more cost-efficient option in the long run.

LED lights come with a wide range of colors and intensities, allowing you to create a customized lighting effect for your aquarium. This not only enhances the aesthetics of your tank but can also benefit the health and growth of your fish and plants.

Tips for Choosing Aquarium LED Lighting

  • Consider the Type of Aquarium: Different types of aquariums require different lighting. For example, a freshwater aquarium with plants will require higher intensity lighting than a freshwater aquarium with just fish. Make sure to choose the right LED lights for your specific aquarium type.
  • Choose the Right Spectrum: The spectrum of light that LED lights emit can impact the health and growth of plants and fish. For example: blue light is good for promoting photosynthesis, while red light can enhance the root growth. Make sure to choose LED lights with the right spectrum for your specific needs.
  • Consider the Intensity: The intensity of LED lights can be adjusted to suit your needs. Make sure to choose LED lights that can be easily adjusted (dimmed) to provide the right amount of light for your aquarium.

We recommend to always start with LED lighting. Just check for a inexpesive solution.

An aquarium LED light will give you stunning results paired with visual appealing look of your underwater world.

Choosing the best aquarium light

Now we have all the key facts covers, we can take a closer look at which light is best for your specific requirements.

What type of light is best for freshwater aquariums?

The best light for freshwater aquariums is any type of LED light. As of today it is the most cost-efficient option with the best color range, ease of maintenance and safety features.

Which aquarium light is the best for planted tanks?

The best aquarium light for plants must include blue and red light waves to promote healthy plant growth. This is ensured by having a color temperature between 5500 K and 7000 K.

It should provide between 38-76 lm per gallon (10-20 lm per liter) and 152 lm per gallon (40 lm per liter) of water depending on the types of plants you want to grow.

What is the best time to turn on aquarium lights?

A good rule of thumb to run the aquarium lights is around 6 - 9 hours per day. This time range is long enough to stimulate plant growth and create a healthy environment for the animals in the tank.

Running your lights for a longer period is possible but could promote algae growth in certain circumstances and might disturb light sensitive animals.

At what time you turn on your lights doesn't really matter much unless your tank also receives a lot of natural sunlight. In this case turning on the aquarium lights outside of daylight hours might significantly increase the overall amount of light your plants and animals receive, which might also lead to the above mentioned problems.

Can I leave my aquarium light on 24/7?

Aquarium lights should never be turned on 24/7 as this is completely unnatural for both plants and animals.

Aquarium light timer

An aquarium light timer is one of the essiantial tools for any aquarium owner. It allows you to set a timer to switch on and off the aquairum lights automatically. This ensures that your fish and plants receive the appropriate amount of light each day and maintain a consistent day and night cycle.

There are two different types of aquarium light timers. The affordable mechanical timers and the more precise digital timers.

In case you are on a budget, we recommend to go with a mechanical timer, as the price difference is not worth it.

Do I need an aquarium night light?

No, you don't need an aquarium night light. Although some aquarium LED lights offer this additional nice-to-have functionality, it doesn't add any value to the health or wellbeing of your animals or plants other then being visually appealing. Simulating moon or night light is done by dimming the lights and giving them a more blueish tone.

Is LED light bad for aquarium fish?

No, LED light is not bad for aquarium fish as long as you consider:

  • The intensity is not more the 230 lumen per gallon (60 lm per liter)
  • The spectrum is between 5500 K and 7000 K
  • The duration is no longer then 12 hours per day
  • The fish have enough shaded space to hide if they like

What is the best LED Aquarium Light?

Ultimately, the best LED aquarium light for you will depend on your specific needs and preferences, as well as the needs of your aquatic plants and fish. It's a good idea to do some research and read reviews before making a purchase.

Known aquatics brands for good quality lights are:

  • ADA
  • ONF
  • Dennerle
  • Fluval
  • Juwel
  • Kessil
  • Nicrew
  • Hygger
  • and many more