Do Angelfish Like Light? Do They Need it?

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Quite often, I wondered whether or not angelfish like or need light. I knew that my tank received sunlight, although I wasn’t quite sure if the amount was enough. Since angelfish are dear to my heart, I began to research the topic a little deeper.

Yes, angelfish like light and probably need it because it leads their inner clock, allowing them to distinguish between day and night. Moreover, sufficient lights will ensure your vegetation flourishes, providing efficient hiding spots and a stress-free environment for your angelfish.

However, if the light is too harsh, your angelfish might be paradoxically stressed. Also, frequent and abrupt changes in daylight might confuse your fish and brighten their stripes. Keep on reading to learn how to avoid these issues and get the best out of your aquarium illumination.

Also Read: Angelfish Tank Setup

Do Angelfish Like Light? Do They Need it?

The best angelfish tanks are designed to replicate the natural conditions the creatures encounter out in the wild. And because angelfish live in tropical environments, you can trust that they get plenty of sunlight. For that reason, you can assume that light is suitable for angelfish.

But it is difficult to determine whether or not they actually need it to survive or the amounts they require. This is because research regarding the impact that light has on angelfish is scarce. 

So most people base the decisions they make regarding the lighting requirements of their angelfish on experiments. Sometimes they rely on the results they have observed with other types of fish.

In other cases, they consider the consequences of the lighting experiments they have performed on their own angelfish. But because angelfish are tropical, it is generally presumed that they require some light.

If you are one of those people who are thoroughly confused by the lighting issue, try to keep the following benefits of lights in mind:

Positive Impact on Pigmentation

Light is good for the color of your angels. Bright lights, in particular, will make the pigments darker, allowing any unique designs and patterns they may have to stand out. This is why some of the more expensive tanks have a lot of sophisticated lighting, particularly in places where the fish are decorative. 

The objective is to highlight their beauty more than anything else.

However, lights that are too bright can cause undue stress in your fish, especially if they have no place to hide. Angelfish can tolerate excessively bright lights, but they can never truly acclimate to them. 

In fact, lights that are too bright have been known to cause the color of angelfish to brighten.

In the wild, even when there are no plants, if the light of the sun becomes unbearable, fish have the option of merely diving deeper to escape its rays.

Lights Lead The Angelfish’s Inner Clock 

Lighting matters to angelfish because they don’t have eyelids, so they can’t block bright light at a moment’s notice. Additionally, their pupils do not adjust like those of a human to control the amount of light entering the eye.

They have rods and cones that will retract and change in reaction to either bright or dim light, but this happens very slowly. This is one reason why new angelfish might flee or react adversely every time you switch the lights in the tank on or off. 

Light doesn’t stay the same in the wild. But changes are gradual. Like most creatures, angelfish have an internal body clock that has been programmed to expect a particular duration of light followed by a specific period of darkness. 

But the shift from darkness to light and vice versa is punctuated by long transition periods at dusk and dawn. The sun cannot suddenly switch on and off. So you cannot blame your angelfish for becoming agitated or frighteningly listless because you switched the tank lights on or off without warning. 

To mimic the conditions your fish experience in the wild, you need to make the transition between darkness and light gradual.

Before switching the tank lights on, first, switch the lights in the room on. Wait a few minutes before turning on the tank’s lights. Do the same thing at night. Switch the tank lights off, but keep the lights in the room on. Give the fish a moment to adjust before switching the room lights off as well.

This gradual shift in the light will allow newer fish to adjust more quickly while also enabling older fish to thrive.

Lights Allow Plants to Flourish

This is the primary reason why every angelfish tank needs lights. Angelfish can survive and even thrive in dim or scarce lighting. However, angelfish also require plants.[1] They use the foliage to hide, spawn, and swim through. Plants, for their part, depend heavily on light for their survival.

Angelfish can survive on the ambient light in a room. However, because ambient light isn’t necessarily reliable, they require supplemental aquarium lighting to remain healthy and active. 

Because freshwater angelfish are tropical creatures, they must be paired with tropical plants like Amazon and Java. Like tropical fish, tropical plants require the same 12 hours of light every day. 

Plants are an essential consideration because their presence will affect your lighting requirements. A tank with only angelfish doesn’t require that much light because, as mentioned above, the scarcity of light won’t adversely affect the health of your fish.

However, the moment you introduce plants to the tank, your lighting requirements increase.

You must provide sufficient light to satisfy the needs of both the fish and their plants. The more plants you have, the more lighting you require.

Also Read: Do Angelfish Need A Filter?

Why Do Angelfish Hide When Exposed to Light?

Don’t presume that angelfish prefer living without light simply because they keep running and hiding whenever you turn the lights on.

This has been known to happen with beginners who have just introduced new angelfish to their tanks. They don’t understand why their angels keep lingering in the shade of the plant life, only emerging when the lights go off.

Despite what beginners think, this behavior does not necessarily prove that angelfish don’t require light. In fact, it should only concern you when it manifests in older fish that have been in your tank for a long time. When you see new angelfish hiding from the light, that is a pure manifestation of stress.

Your tank is still alien territory to them, and they haven’t acclimated to it yet. So it is quite natural for them to run for cover whenever a shocking transformation such as the manifestation of light occurs. Given enough time, your angels will grow accustomed to their new home. 

On a side note, if your new fish keep hiding from the light, they are probably the shy type. Keep that in mind in case further complications arise down the line.

On another side note, this is why plants are so crucial to angelfish. They need the foliage to hide in times of stress. It allows them to feel more secure, which, in turn, alleviates their stress.

How Long Should Angelfish Be Exposed to Lights?

How many hours of light do angelfish require? This question is so much easier to answer than people realize. The amount of light any fish species requires depends on the conditions you find in its natural habitat.[2]

Angelfish are tropical fish that get roughly 12 hours of light every single day. These conditions remain mostly unchanged throughout the year. So you are encouraged to keep the lights in your tank on for roughly 12 hours per day. 

In fact, you don’t have to make any notable changes. Angelfish expect the same amount of light as humans. They hope to experience a regular day/night cycle. 

Once the day comes to an end, and the sun sets, you are free to switch the lights off. You are also free to wait until bedtime to switch the lights off. This allows the fish an opportunity to rest. Angelfish tend to become inactive when the room goes dark.

Here is something I’ve learned over the years – rather than worrying about switching the tank lights on and off at the right time, install a timer that can do this automatically.

What Should Be My Angelfish Light Source?

You are encouraged to install lights on every angelfish tank you buy. However, just because you have the lights in place doesn’t mean you should use them. Sometimes, the ambient light in a room is more than enough to meet the lighting needs of your fish.

If the room in which the tank is positioned is adequately illuminated by the sun (or other sources of light such as bulbs and lamps), you can keep the tank lights off.

But you still need the tank lights in place because ambient light is unreliable. It tends to fluctuate, especially in the winter. You can use the tank lights to supplement the ambient lighting where necessary.

What If the Lights Will Hasten Algae’s Growth?

It was argued above that your tank needs adequate light because plants need it to thrive. This is a good thing for ordinary plants that act as a sanctuary for your angelfish. It is a bad thing because sufficient light will also cause algae to grow.[3]

The more light an aquarium receives, the faster the algae will grow. Algae is not suitable for tanks. It makes the tank look dirty while also competing for resources with your plants. This forces you to clean the aquarium more frequently. 

But the threat of algae isn’t an excuse to take the lighting away from your angelfish. Instead, you should reduce the time during which the lights in your tank are on. Bring it down from 12 hours to 8 hours. 

You should also avoid sunlight. Algae grow faster in the presence of direct sunlight than it does with artificial light. If your algae problem is getting out of control, stop relying on the light of the sun.

Also Read: Best Substrate For Angelfish

What Kind of Lightning Should I Get For My Angelfish?

When it comes to buying lights for your tank, prioritize LED Lights. Incandescent, metal halide, and VHO Fluorescent lights are sufficiently bright. 

However, when used within the confines of a small tank, they will increase the temperature of the water, potentially killing the fish and plants. LED lights, on the other hand, are cheap and relatively cool.[4] The same goes for standard fluorescent lamps.


There is no doubt that light is a crucial factor when it comes to angelfish. Frankly, I believe getting the right balance is essential to almost every kind of fish. The key here is to keep things as they are in the fish’s natural habitat.

Angelfish are originated from the Amazon Basin. That, in turn, receives a decent amount of light during the day-time. The same thing should be in your aquarium. Keep in mind that you don’t exceed 12 hours of lightning and that the on and off switches are not abrupt. 

The best way to know your angelfish lightning requirements is by experimenting. Make your adjustments and see how your fish behave and appear. Over time, it will become your sixth sense.