Skip to Content

Are Angelfish Nocturnal? (And Do They Need Light?)

Are Angelfish Nocturnal? (And Do They Need Light?)

Share this post:

This post is written to the author's best knowledge and is not intended to be used in place of veterinary advice. In addition, this post may contain affiliate links. As an Amazon Associate I earn from qualifying purchases.

Angelfish are definitely among the most well-loved pet fish. If you have some of them in your fish tank already, then you already know that they’re beautiful.

These graceful fish can bring a lot of color and joy to your fish tank. If you’ve only just added the fish to the aquarium, then you might still be learning how to care for them.

You could even be wondering whether these fish are nocturnal. Do angelfish stay more active during the night or are they diurnal?

Read on to learn a bit more about angelfish and whether they’re nocturnal or diurnal. This should make it simpler for you to understand the needs of the fish as a new angelfish owner.

Angelfish Are Diurnal

Angelfish are not nocturnal at all. They are diurnal fish, and this means that they generally “sleep” during the night.

When talking about wild angelfish, you’ll find that they usually stay around the shallows of the coral reef. They don’t usually go much deeper than fifty meters.

During the night, wild angelfish hide in the different crevices of the reef so that they can get some rest. They need this period of rest since they have to recover strength.

When nighttime falls, the mobility of the angelfish will be significantly reduced. The fish are far less active once the night arrives.

Captive angelfish will be very similar to wild angelfish when it comes to what they do at night. The angelfish won’t swim around much, and most will try to find good spots to sleep.

You’ll find angelfish sitting at the bottom of the tank during the nighttime hours. Some might attempt to hide in various spots, too.

If you look closely, you might see angelfish hiding in the aquarium rocks or among the live plants that you placed in the tank. Your fish will be resting at night, and they’ll be more active again when the morning comes.

Are Angelfish Capable of Seeing in the Dark?

Silver Angelfish Swimming in the Dark

If you’re wondering whether angelfish can see in the dark, then you’ll be interested to hear that they cannot. Angelfish will not be able to see well at all in the dark.

This is why your fish need lights to be able to see in the fish tank. If you want your fish to be able to see at night, then you’d need to leave some lights on.

However, it’s not good to leave bright lights on during the night. This could keep the fish from being able to sleep, and it’d mess up the day and night cycle for the fish.

For this reason, you should only have soft lights on at night. Some people keep the lights off completely during the night, but it’s up to you to decide which route to take.

There are these lights that are known as “moonlights” that you can buy for aquariums. Basically, these are lights that are meant to replicate the look of moonlight.

The fish don’t need these lights, but they can be cool to own. They make the aquarium look more aesthetically pleasing at night.

If you plan to spend time staring at the fish tank at night, then it’d be good to have some moonlights. Otherwise, they aren’t completely necessary.

Do Angelfish Need Light?

Yes, angelfish need to have light to be able to see. If you kept things dark, then the angelfish wouldn’t be able to see what they’re doing.

You should keep lights on during the day so that the angelfish can experience a normal day and night cycle. This is easy to achieve, and you have likely been doing this already if you have an aquarium set up in your home.

It’s also notable that any plants that you have in the tank will require light. Aquatic plants need light just the same as standard land-based plants do.

If you don’t have some sort of light source, then the live plants in the fish tank won’t be able to keep growing. Plants are an important part of the fish tank, and this is just another reason why lights matter so much.

You should know that plants are crucial when you’re caring for angelfish. Angelfish might get stressed if they don’t have plants in the aquarium.

The plants help the fish to feel more natural and at ease. You should add good plants to the aquarium that angelfish are known to like, such as Amazon Sword and Jungle Val.

Do Angelfish Fry Need Light?

Angelfish Fry

The light requirements of angelfish fry are just the same as mature angelfish. Once the fry reach the free swimmer stage, they’re going to become panicked if they experience sudden light changes.

You should ensure that the angelfish fry have light so that they can see what they’re doing. The normal lights that you’re using for the rest of the tank will be just fine.

It is worth noting that angelfish parents might panic while protecting their eggs if the lights suddenly shut off. This could cause them to eat the eggs out of worry.

For this reason, many angelfish owners choose to shine a soft night light of some sort at the area where the angelfish parents are protecting the eggs. This ensures that the angelfish can see what they’re doing to protect the eggs at all times.

Do Angelfish Sleep at Night?

At night, angelfish will essentially go to sleep. Sleep is a bit different for fish than it is for humans, though.

Some fish enthusiasts don’t like to use the term sleep when referring to what fish do at night. Others find it a very appropriate word to use since the fish are resting up.

Basically, the angelfish will enter a resting state where it will still be alert enough to react if it comes under attack. There are land-based animals that do things such as this too.

For example, a deer can go to sleep, but it’ll remain aware of its surroundings. This makes it so that the deer will pop up and run away at a moment’s notice, and that makes it very hard to sneak up on a deer.

Angelfish are kind of like this since they don’t enter a deep sleep. They’re just resting, and they don’t experience REM sleep or enter a state of unconsciousness at any time.

Can You Keep Angelfish in a Tank with Nocturnal Fish?

Marble Blue Angelfish Swimming in the Dark

Now that you know that angelfish are diurnal, you might be wondering if they can stay in a tank with fish that are nocturnal. This shouldn’t be a problem so long as you do things right.

Firstly, you can only place angelfish in a community tank with fish that they’re compatible with. Angelfish are a mildly aggressive type of fish, and they will eat fish that are smaller than them.

You also can’t put them in tanks with larger fish that will bully them. If you want to keep all of your fish safe, then you need to look into compatibility ahead of time.

If you can find nocturnal fish that are compatible with angelfish, then it shouldn’t be a problem. Just do your homework so that you don’t wind up putting fish in the tank with your angels that will be problematic.

As you’ve learned, the fish are going to need to have a day and night cycle. This means that you don’t want to have bright lights on at night.

The moonlights that were mentioned earlier will be very useful when you have nocturnal fish in your community tank. These soft lights won’t bother the diurnal fish that are trying to sleep at night.

They will be just bright enough that the nocturnal fish will be able to see what they’re doing. With these lights installed, you’ll be able to enjoy both nocturnal and diurnal fish in the same home aquarium.

Moonlights are definitely useful for reasons other than providing aesthetic appeal. They aren’t that expensive, and you’ll love utilizing them.

Final Thoughts

After learning more about angelfish, you now know that they are not nocturnal fish. The angelfish that you buy from the pet store are diurnal fish, and this means that they go to sleep at night.

Angelfish need to have a normal day and night cycle to stay healthy. Otherwise, the fish might become stressed, and this could weaken their immune systems.

Fish with weakened immune systems will be more susceptible to diseases and parasitic infections. You don’t want this to occur, and that’s why it’s imperative to pay attention to what you’re doing with the lights.

The lights should be on during the day, but they should be turned off at night. You can keep some lights on at night if they’re the right types of lights that won’t bother sleeping fish.

Moonlights are ideal because they’re very soft and won’t prevent the fish from sleeping at night. They will allow nocturnal fish to see at night if you happen to have some in your tank.

Angelfish can’t see in the dark either, and when they’re protecting their eggs, they might need light during the night. In this situation, you should keep some soft light on so that the angelfish won’t panic and choose to eat their eggs.

You know what you need to know now. Just continue to care for your angelfish and have fun observing them in your tank.

Share this post: