Fish

Myth Busted – Do Fish need Light in Aquarium?

If you are a new aquarist, you would perhaps find it much annoying and confusing to decide if fish in the auarium need light. It can be very difficult to decide if you need to keep the light on or off. How long should the aquarium light be on? Let us learn if it is essential to keep the aquarium light on at night or should you the light off. We will also learn what the light means for the fish in the aquarium.

Quick Answer –

Yes, the fish in the aquarium need light. it will help them understand if it s day or night. However, you need not provide artificial light using the aquarium lighting. They can be comfortable with the natural light in your room. In essence, fish do not get the kind of light in the wild that you provide them in an aquarium. Thus you can comfortably turn the light off at night.

Do the  Fish in Aquarium Need Light?

Whether the fish in your aquarium need light or night is dependent on what you have kept in an aquarium. In case your aquarium has the fish alone, you may not need the artificial lighting. The natural light in your room should be sufficient to provide relief to your fish. Since they get the kind of light that they get in the wild, they will not have any issues whatsoever. However, if you have a planted aquarium, you may need artificial lights. Plants need good amount of light for photosynthesis.

 

Using intense lighting in the aquarium is not recommended by most of aquarium experts. Too bright light may make your fish hide. While, natural light is enough for most of the purposes of the fish in the aquarium, using artificial lights or moderately bright lights can help bring out the bright colours of the fish and help in their overall growth.

 Can Fish Sleep with Light On?

Fish do not need complete darkness to sleep. However, it is good to provide them with the same amount of light that they would get in their natural environment. Since most fish are diurnal, and can only sleep during the night, it is good idea to turn off the aquarium light at night. 

A 24 hour light may stress the fish. You should plan the light as per the proper day – night cycle. Fish can sleep if they are tired even if there is light. But, for a good quality of sleep and a better well-being, the fish should ideally sleep in darkness.

Do Aquarium Fish Need Sunlight?

Fish typically need light to find food. They do not need direct sunlight. A normal room light should be sufficient for them. Of course, some fish may like the sunlight. But, it is not advisable to install your aquarium under sunlight at any cost. It can cause an increased algae growth and high temperatures.

Fish can live comfortably in darkness, but they may not get food. If you do not have proper light, the algae will not be able to produce food. You can provide around 12-16 hours and a dark period of 12-8 hours. But, it isn’t needed to provide any sort of direct sunlight as such. Keeping your tank in sunlight can make the fish suffer. It can also turn the water green by supporting a huge algae growth.

What Kind Of Lighting Do Fish Need?

Fish will prefer LED light in the aquarium. This is because the light from the LEDs is consistent over time and does not generally fade. This mimics the natural light that the fish can get used to. That apart, LED lights in the fish tank do not use much energy. Thus they result in low heat. Thus, you need not worry about your tank getting overheated.

Having said that, there are different types of aquarium light options available. You can analyse the options available to you and choose the one that best meets your needs.

1. LED lights

The LED lights are known to produce a good shimmering effect. These also produce less heat, and make it comfortable for the fish to thrive even when they are on for longer hours. They can also improve the overall look of your aquarium. Yet another advantage that you can get from them is that they offer longer lifespan, quite an energy efficient, and provide multiple color combination options.

2. Full Spectrum Lights

These bulbs emit light quite similar to daylight or natural light. The full spectrum lights emit the light in multiple wavelengths, making them extremely suitable if you have a planted aquarium. The multi-wavelength functionality ensures that the plants can find it better for photosynthesis.

3. Actinic Lights

Actinic lights work as additional daylight options. They are optional and help you illuminate the tank further. These lights normally emit a fluorescent blue light that tends to be quite pleasing for humans and fish alike. Once again, just like full spectrum lights, they are extremely useful for photosynthesis.

4. Incandescent lights

If you have a small tank, I would recommend an incandescent light for your aquarium. However, they have one caveat. They can produce a lot of heat and can be detrimental to the proper equilibrium of the tank and its inhabitants. Moreover, they can offer you a lifespan of around 1000 hours only.

5. Flourescent lights

Though not widely, but fluorescent lights are another type of light used in an aquarium. These types of lights are widely used as they are widely available and are quite energy efficient. You can buy them in multiple shades, sizes and types. You can use them in both saltwater and freshwater tanks.

Takeaway - Do fish need darkness to sleep?

No, fish do not need darkness to sleep. However, the light can affect their sleep patterns. Since fish do not have eyelids as most other animals do. That would mean that they do not “sleep” in the conventional sense that most other fish would do. They will go through a state where the activity is reduced, and the fish will recuperate. This is actually called a sleep-like state than actual sleep.

Even when they do not need darkness, they prefer to sleep in the dark. It is quite advisable to provide them with enough darkness, in tune with what they would get in the natural environment.

Do Tropical Fish Need Light in Aquarium?

Yes, Tropical fish do need light to differentiate between day and night. However, if your room has sufficient natural light, it should be enough. The aquarium lights are needed for us to see the fish and support photosynthesis if you have live plants in the aquarium. 

Aquarium fish- both tropical and otherwise need 8 to 10 hours of light. The light source can either be natural or artificial. If your placement of the aquarium receives enough natural light, you do not need to add artificial light. However, additional light may be needed when you want to see the fish in the aquarium.

Light is important for almost all life in the aquarium, and it includes fish, plants, corals, and bacteria. If you are using artificial light, it is important to match the light and dark conditions of the outside environment.

How Much Light do Fish Need a Day?

Under ideal conditions, your aquarium needs around 10 to 12 hours of light per day. If your aquarium is new, you will need to keep the light on for around 8 to 10 hours. You can then increase the duration by one hour in gradual phases. However, in most of cases, the fish in the aquarium will need just around 10 hours of light per day.

do fissh need light in aquarium
Excessive light can disturb the fish

Ideally speaking, fish do not have a biological need for any sort of light. However, if you have a planted aquarium, it is important to provide enough light. I would suggest stopping at 12 hours at the maximum per day.

The typical duration for the aquarium light can be as per the following outline –

Live Plants in the aquarium

If you have plants in your aquarium, you need to provide them with enough light for them to survive. For most of the plants, an eight-hour lighting should be enough. However, check what type of plants you have in your planted tank. Some types of plants may require 12 hours of lighting. 

However, keeping the lights on for long hours can cause a huge algae growth.  I normally suggest people who consult me to keep the lights on for 8 hours initially and check for sign of algal growth. If you find no such issues, you can gradually increase the duration – checking for algae growth after each increment.

Tropical fish

If your tank has tropical fish, they would generally need at least 12 hours of light. Make sure that you make a beginning with 10 hours initially for checking the algae growth. Increase the duration to 12 hours gradually. The 12 hour duration is essential for the recreation of the tropical conditions.

Saltwater fish

The saltwater fish, on the other hand, require 8 to 10 hours of light per day. This can help in simulating the natural environment in the sea and oceans.

Recommende reading – 6 Shocking Reasons Your Betta Fish Disappeared from tank!

Can Excessive Light Affect Fish in the Aquarium?

Yes, excessive light can affect the proper metabolic functioning of the fish. They almost follow the circadian clock that almost every animal on the earth follows. It can cause an overgrowth of algae to begin with. This can result in lowering the oxygen level in the tank. Too much light can also increase the temperature of the water, which can be another issue for the fish.

As far as my personal experience goes, the prime result of the excessive light in the aquarium is the growth of algae. This can reduce the oxygen available for the fish and also increase the pH level considerably. In fact, the algal growth can severely impact the water quality in your aquarium. Aquarium fish need light, but it is important to pay attention to the amount of light as well.

Too much light can also disturb te sleep patterns of the fish. Since fish belong to different sleep patterns, the light can severely impact the way your fish can sleep and impact their overall health.

Takeaway - Some of the signs of too much light in thee aquarium can include
  • Loss of appetite
  • Disturbed sleep patterns
  • Color fade
  • Anxiety
  • Aggression
  • Lack of immunity

Also recommended – Fishkeeping Myths Debunked – 12 Myths Surounding Fish that You Always Believed in!

Can Low Light have Negative Impact on Fish Health?

Fish can generally live fine in darkness for hours together. However, most of the species would need the combination of light and darkness to help them maintain their natural biorhythm. Just like other animals, fish need light to let their bodies know when it is time to be active, and they need darkness for them to take rest.

Low light in an aquarium can make your fish behave sluggishly. It can also make them lose color and be very less responsive. In addition, I have also observed that low light can induce stress and thus result in behavioural issues. If you have planted aquarium, low light can deplete the oxygen levels. It can also result in additional issues such as respiratory problems, stress, loss of appetite, swimming problems, labored breathing, and other health-related issues.

Do Fish need light to survive in the Aquarium?

Fish may survive in the darkness for some time or even some days. But prolonged exposure to darkness or lack of light can make them suffer. They may begin to wither and finally die. Ideally speaking, fish do not need light biologically to survive, however, lack of  a proper day and night cycle may make them suffer and experience a stunted growth. 

A regular day and night cycle can be helpful in ensuring that fish can regulate their sleep, and overall behaviour. Being a aquarist myself for over three to four years now, what I have understood based on my personal experience is that the fish thrive well when you provide them with the similar light and darkness cycle they experience in their natural habitat. If you leave thee light on all through the 24 hours, it can make the fish lose track of the day and night cycle. In addition, leaving the light on whole day can also cause an excessive algal growth.

What is the Best Color Temperature needed for Aquarium Fish?

The ideal light temperature that a fish would need can be in the range of 5500 to 6500 Kelvin. Given the fact that the afternoon light generally tends to have a 5500 Kelvin rating, it is quite enough to opt for a light that offers a color temperature in that range.

The most natural light would be in the range of 6500 to 6700 Kelvvin, which is what we get from the sun. However, if you have lot of plants in your aquarium, it is advisable to use a light that provides you an average of 10000 Kelvin. If you have only fish, you can consider a color temperature of around 5500 to 6000 Kelvin.

Will the Fish Die without Light?

Theoretically speaking, fish do not have the biological need for light. They do not need any sort of artificial light to survive. That would mean the natural light in your room should be sufficient for the fish to survive and go with its regular routine. Fish need light to differentiate between day and night, and natural light should be enough for this purpose.

However, if you have a planted aquarium, the plant will need light for photosynthesis. In such a case, you will need to provide artificial light in such a way that it does not affect the circadian rhythm of your fish.

Should I Turn My Aquarium Lights off at Night?

It is highly recommended to turn off the aquarium light at night. Aquarium fish do not need light as such, and they can be fine with the natural light in your room. It is, therefore the best option to turn off light at night. Leaving the light on during the night can stress the fish as they may experience disturbance with their circadian clock.

However, simply turning off the lights may make them frightened. Try to follow the natural way of dimming the light. If your lighting system allows you to dim the lights gradually before turning them off completely, that would perhaps be a good option to follow.

The Closing Thoughts

Even when it may not be a necessity, keeping the adequate lighting in the aquarium can be the most important option. This can go a long way in making sure that your aquarium and its inhabitants in the best of health. While you can use different types of lighting options, it is recommended to use LED lights as they tend to offer the most natural atmosphere for the fish in the tank.

On average, it is advisable to keep the lights on in an aquarium on for at least 8 to 12 hours. Check for the conditions like algae growth and adjust the timing as per the exact needs of your aquarium.

A few FAQs

Can fish service without light in the aquarium? 

Unlike the other animals, fish do not need light. They would be fine with the natural light available in your aquarium. If your room has enough natural light, and it is in the range of 5500 Kelvin, your fish should have no problem with proper functioning.

Are LED lights bad for fish?

No, LED lights are better options for aquarium lighting as they do not generate heat. Moreover, they can be adjusted for the right color temperature. If you are wondering if LED lights are fine for your fish, you would be glad to know that LED lights are never harmful for your fish in the tank.

Does the aquarium need light at night?

The aquarium does not need any light in general, and as such it is fine to turn off lights in the aquarium in the night. Leaving the light on can stress out your fish as they need a period of darkness for proper sleep and rest. Too much light can also cause algae growth and can affect the water quality. This can further cause health and other issues for your fish.

Do fish need light to eat?

Yes, fish need light to eat as finding food in the dark can be difficult. Of course, fish rely upon a good night vision to swim in the darkness, but they may not be able to find food that easily if it is too dark. However, I would recommend turning off the lights when feeding, as the light can go into their eyes and can be counterproductive as they may find it difficult to find food. But, you will need to make sure that natural light is available when feeding.

About the author

Timmappa Kamat

Timmappa Kamat is a pet lover and a dedicated writer specializing in the captivating world of pets. He brings a wealth of knowledge and expertise to DreamyMammals. He grew up surrounded by pets since his childhood and this made him develop a connection with animals. This has sparked a lifelong curiosity for understanding and communicating with pets.
Writing style of Timmappa Kamat is characterised by a warm and friendly tone, making complex pet-related topics accessible to readers of all backgrounds. He loves sharing the animal behaviour with a persoanl touch. He creates articles that resonate with pet owners, thanks to their relatable and informative nature.

Add Comment

Click here to post a comment

About Author

Timmappa Kamat

Timmappa Kamat is a pet lover and a dedicated writer specializing in the captivating world of pets. He brings a wealth of knowledge and expertise to DreamyMammals. He grew up surrounded by pets since his childhood and this made him develop a connection with animals. This has sparked a lifelong curiosity for understanding and communicating with pets.
Writing style of Timmappa Kamat is characterised by a warm and friendly tone, making complex pet-related topics accessible to readers of all backgrounds. He loves sharing the animal behaviour with a persoanl touch. He creates articles that resonate with pet owners, thanks to their relatable and informative nature.