Do Cardinal Tetras Need Light At Night?

Cardinal tetras aren’t demanding fish in any way. But they do have a couple of rather specific requirements when it comes to their environment. Most aquarists prefer an aquarium in proper lightings to help in the growth of Cardinal tetras. But do you think Cardinal tetras need light at night too?

No, Cardinal tetras do not need light at night. But it is a good idea to have some form of light in the aquarium throughout the day and night so that you can supervise your fish in the dark. You need to remember that Cardinal tetras do not need more than 12 hours of lighting, and lights mimic natural sunlight.

If you are new to fish keeping, you have any questions about Cardinal tetras’ needs. So, today we will cover all the things you need to know about their need for light and what you can use to supply the light.

Do Cardinal Tetras Need Light At Night?

No, Cardinal tetras do not need light at night. Cardinal tetras follow a circadian rhythm similar to humans. When exposed to sunlight, these fish feel sleepy and not active throughout the day. But when there is no light exposure during night time, they are more lively.

However, Cardinal tetras also need to sleep for many hours with no light exposure during the day. So there should be some time of low or indirect lighting in their environment which might make them feel comfortable and happy during the daytime.

Besides this, Cardinal tetras are more active at night, and you need to keep them in a well-planted aquarium. They like swimming through the plants and exploring different areas of their tanks at night time.

If you don’t provide light sources at nighttime, they are more likely to bump in plants, rocks, or decorations. Some fish species become more active at night. It can be a problem for the Cardinal tetras if you keep them with other nocturnal fish species.

What Are The Benefits Of Lights In Cardinal Tetras Aquarium?

There are many benefits of lights in cardinal tetras aquarium which you should know. Some of them are:

Promotes Growth Of Plants

Cardinal tetras need light at night to grow the plants inside their tank. If you do not use lights, it can affect your plant growth and cause problems in their health. So, always ensure that cardinal tetras aquarium has good lighting so they might get enough sunlight throughout the day, which is very important for the growth of plants.

Maintains Water Temperature

Lights in the aquarium can help you maintain the water temperature. The ideal time for lights is when they are on from sunset to sunrise, which will allow your tank’s heater and an air pump to work more efficiently since they won’t have to do it all day long. Also, regular monitoring helps to meet the water requirements of Cardinal tetras.

Prevents Cardinal Tetras From Accidents

Cardinal tetras are nocturnal. Because of this, cardinal tetra fish tanks should have lights in them so that the tank’s inhabitants won’t wander around at night and accidentally fall off or stick somewhere they shouldn’t be.

Lights in the aquarium provide you with a better view of your plants and fish. So, it protects Cardinal tetras from bumping into objects, and your fish will see better.

Helps In Supervision

If you want to keep watch on your cardinal tetras, lights in the fish tank will help. You can observe them more closely during day or night time since different kinds of lighting allow for this flexibility.

With the proper lighting for the aquarium, your tank waters become more lively and stimulating. Under bright light, nothing can hide from view because of its brightness. It is also lovely to look at the cardinal tetras swimming in the aquarium with rays.

Why Would I Need To Avoid Lights At Night For My Cardinal Tetra?

Although lights in the cardinal tetra’s aquarium can serve many benefits, there are times when you should avoid them at night for your fish. For example, some cardinal tetra diseases occur due to a lack of rest. Thus, it’s best not to have any lights on during the night for your cardinal tetra.

Besides this, if you do have lights on at night, there are risks to it. Cardinal tetras can burn in too much light. It could lead to diseases or death, so avoid bright lighting in their tank while they sleep. It would be best if you also avoided overhead lighting while your tetras are resting because it can disrupt their circadian rhythm and cause them to get sick as well.

How Much Light Do Cardinal Tetras Need?

Cardinal tetras do not have a lot of lighting. They prefer dim lighting in a way that mimics the natural environment. For example, they need the lighting to help them see their food to eat it and stay healthy.

Usually, Cardinal tetras need around 12-14 hours of light per day. However, they need to be able to have some time without any lighting at all.

They are not familiar with bright lights with high wattage because most natural environments have dim lights and usually have floating plants for cover. Keep this in mind when you are thinking about buying a tank light or what kind of plant life you want to include in the tank.

A good rule of thumb is to have around 0.75 watts per gallon for a community tank (a few cardinal tetras and other fish). So you can add up at least three Watts per Gallon.

Do Cardinal Tetras Prefer Darkness?

Cardinal tetras are a very easy-going group of fish. They do not need a lot of attention or care, and they can adapt to just about any tank conditions you provide for them, which makes them an excellent beginner species (Be sure to keep their water clean).

There is one aspect that some people argue over, though. Some believe that Cardinal tetras need light at night to survive. While others think you need to leave fishes in darkness because it will make them feel more secure and comfortable in the aquarium environment.

But since their natural environment is dark and underwater, some people believe it is best to keep them in the dark at night, and the lights need to turn off. But whether these fish enjoy light or darkness is still up for debate. It is because every fish show different behaviors when it comes to lighting.

So, you will have to figure out what is best for your Cardinal tetras based on their needs.

What Are The Best Lights For Cardinal Tetras?

There are many different types of lights out there, but the best for cardinal tetras is LEDs. LED stands for “light-emitting diodes” and fits the bill perfectly for cardinal tetras.

LED lights are best because they come in a variety of colors. You can also customize them with unique programs that change throughout the day. These programs include unique designs to promote sleep at night and have an extremely long lifespan, reducing your maintenance needs.


In conclusion, if you worry about the lighting in your aquarium, it is best to have some dimly lit lights. It will allow them to see their food and feel secure at night without bright lights shining into their eyes or disrupting their circadian rhythm with bright overhead lighting.

Hopefully, this settles some of your doubts. For more information, you can visit our website or contact us through mail or comments.

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