Emperor Angelfish: The Ultimate Guide to Care, Breeding, Tank Size and More

The emperor angelfish is a stunning saltwater fish that will wow your guests with its beautiful colors and patterns. But be warned, this fish is not for beginners!

Emperor Angelfish – Quick Facts

In a rush? Check out the quick facts about Emperor Angelfish below.

Fish Info

Scientific NamePomacanthus imperator
Common NamesEmperor Angelfish, Imperial Angelfish, Imperator Angelfish
AppearanceThe Emperor Angelfish is dark blue and yellow, with white and electric blue rings.
DifficultyEmperor angelfish are quite difficult to care for because they live in deep, biologically rich, saltwater habitats.
DistributionThe emperor angelfish has a wide Indo-Pacific distribution. It occurs from the Red Sea southwards along the East African coast to Hawaii.
LifespanThe lifespan of emperor angelfish is about 20 years.
TemperamentEmperor angelfish are territorial and aggressive.
Keep in Groups ofOne emperor angelfish should be kept per tank, but two can be kept if the tank is large enough.
Tank MatesDottybacks, Six-line and 8-line wrasse, Damselfish, Tangs, Large wrasses, Butterflyfish, Sohal Tang, Blue Tang, Yellow Tang, Powder blue Tang, Brown Tang, Achilles Tang
DietEmperor angelfish are omnivores that feed on small invertebrates and plants, with a preference for sponges and algae.
LengthThe emperor angelfish grows to 15 inches in length in the wild but only 12 inches in captivity.
Sexual DimorphismThe male is larger with blackish pelvic fins and a yellow spot on the caudal peduncle, while the female has orange pelvic fins.
Breeding DifficultyIt is very difficult to breed emperor angelfish in captivity.

Water/Tank Recommendations

Water TypeSaltwater
Water TemperatureThe ideal water temperature for emperor angelfish is 72-82°F (22-28°C).
Water pHThe ideal water pH for emperor angelfish is 8.1 to 8.4.
Water HardnessThe ideal water hardness for emperor angelfish is 8 to 12 dGH.
Tank sizeThe minimum tank size for emperor angelfish is 125 gallons, and the recommended tank size is 200 gallons.


Emperor Angelfish are a stunning saltwater fish that can bring a ton of life and movement to your tank. But looking after this fish and running a saltwater tank come with their fair share of requirements.

This comprehensive guide will show you all there is to know about caring for Emperor Angelfish in your home aquarium. You’ll learn about their diet, lifespan, size, habitat tank recommendations, and more!

About Emperor Angelfish

Emperor angelfish can be found throughout the Indo-Pacific. These fish are named after their striking blue stripes, which resemble an emperor’s robe.

This species is one of the largest saltwater angelfish in existence. They have a reputation for being difficult to keep and requiring large aquariums or outdoor ponds. This has led to decreased popularity over the years, but there’s no denying that they make beautiful additions to any marine tank!

Emperor angelfish can reach lengths of 15 inches when fully grown (although this length might not be sustainable in captivity, 12 inches is more realistic in this case). Their bright colors help these fish stand out against dark waters filled with coral reefs and rocks.


The emperor angelfish is a stunning fish with bold stripes and spots. When it comes to color, this species is not shy! The base body color of the fish is dark blue.

This shade can vary slightly between individuals but will be pretty uniform within any one group or collection. This gives them an almost night-like appearance when they swim through your tank (especially if you have subdued lighting).

Across the length of their bodies are electric blue vertical stripes that begin at the tip of their nose and run back until they fade into white on their caudal fin.

When you examine these stripes up close, you’ll notice that small dots are also running along them. These dots create some very interesting visual effects as your angelfish swims about in your aquarium!

Their Length

As mentioned earlier, the length of an adult emperor angelfish in the wild is around 15 inches, but it’s not unheard of for them to reach lengths exceeding 20 inches!

In comparison, most aquarium specimens only grow to about 12 inches.

This is due to the fact that wild emperor angelfish live in deep, biological-rich habitats. Their environment has everything they need to reach their full potential.

In captivity, they’re still pretty impressive. They make stunning fish for large tanks (more on that later).


As we stated previously, the average lifetime of an emperor angelfish is about 20 years. This means they can live quite a bit longer than some other saltwater fish you might be interested in keeping.

But then again, there are no certainties when it comes to their life expectancy (just like any other fish). If you want your angelfish to surpass that 20-year mark, then make sure you do everything possible to provide them with a great habitat.

Sexual Dimorphism

There is some subtle sexual dimorphism between male and female emperor angelfish. Both are generally blue in color with white rings around their body, although there can be some variance.

The most significant difference is in their size. The males are slightly larger. The male also has darker, blackish pelvic fins and a yellow spot on the caudal peduncle, while the female has orange pelvic fins.


The Emperor Angelfish prefers waters that are deep and rich with life. It’s usually found at depths of 50 to 300 feet. They live in coral reefs and lagoons, preferring environments with plenty of hiding places.

A lot of their time is spent at the bottom of the water column, feeding off plants and small organisms like worms.

Caring for Emperor Angelfish

Emperor angelfish require a lot of attention when it comes to their care. These fish are considered quite difficult to care for, but this doesn’t mean they aren’t worth the trouble!

The secret lies in recognizing their distinctive needs and committing to providing them with a suitable environment. Here, we’ll touch on everything you ought to be aware of caring for your emperor angelfish.

Caring for these fish can be a challenge, but there are many benefits to doing so. Emperor angelfish make superb additions to large aquariums and are stunning creatures that never get boring!


Emperor angelfish are omnivores that feed on small invertebrates and plants, with a preference for sponges and algae. They will also eat any live or frozen foods as well as flake food.

In addition to their natural diet, you can provide them with chopped-up shrimp, fish fillets, vegetables such as spinach or cucumbers (which many aquarists like because it’s fun to watch the fish swim through it), plankton from time to time, brine shrimp and enriched pellets.

How Often & How Much to Feed Them

The ideal way to feed your angelfish is twice a day. Provide small meals each time and make sure that the amount of food they get isn’t too big or too small. They

You should feed them as much food as they can finish within about 5 minutes. You’re probably overfeeding them if they’re still eating after this point!

Possible Diseases

Emperor angelfish are susceptible to all the usual saltwater fish diseases. The most common issues that plague these beautiful creatures include Ich and bacterial infections.

Ich is highly contagious, so quarantine tanks are needed if you plan on introducing new animals into your tank. weekly water changes.

Tank Setup

A well-planned tank is essential for the well-being of your angelfish. Emperor angelfish are very demanding when it comes to their habitat, so you must create a habitat that is nearly identical to their original environment.

Creating a natural environment means starting with live rock and sand substrate at the bottom of the tank (following good aquarium cleaning practices). The deep ocean floor usually has plenty of hiding spaces where these fish can feel safe and confident within the aquarium.

Next, add several pieces of rock throughout the tank along with numerous plants, including Java ferns, Anubias barteri, Cryptocoryne spp., or other hardy species (again following proper planting practices).

Aquarium Size

The minimum tank size for emperor angelfish is 125 gallons, and the recommended tank size is 200 gallons. This can vary depending on how many fish you want to keep together.

You’ll need a deep aquarium, too, with some tall open space at the top of your water column. The deeper it is, the more flexibility they will have when choosing where they go. A shallow tank won’t provide enough options and could spark aggressive behavior.

Water Conditions

The species does best in warmer waters with low nitrates and a pH balance that is slightly more alkaline.

If you want your fish to thrive, perform weekly water changes of 20 percent or more with an efficient filtration system. This will help keep ammonia levels at bay, which can stress the fish out and even kill them.


The water conditions in the natural habitat of emperor angelfish are very stable. It’s best to replicate those same conditions in captivity.

The pH levels should be slightly alkaline, ranging between 8.1 and 8.4.

Test the water regularly to ensure that levels don’t fluctuate. These fish react negatively to any sudden change in environment, and slight fluctuations can wreak havoc on their immune systems.


The water temperature in Emperor Angelfish’s natural habitat is between 72 and 82°F, but it can tolerate a range from 68 to 86°F, so you have some flexibility when it comes to tank temperatures.

The only thing that cannot be compromised on is consistency: wild angelfish live in warm waters with stable temperatures. This means you must do everything possible to ensure that your aquarium replicates its natural environment as closely as possible.


The ideal hardness for emperor angelfish is 8 to 12 dGH.


Emperor angelfish do well with a good filtration system. Use a canister filter and perform weekly water changes to keep ammonia levels low.

A small protein skimmer is another useful technology that you can add to your tank, as it removes organic matter from the water. It also keeps nitrate levels low.

NOTE: Make sure that your filtration equipment has enough power to cycle the entire aquarium effectively. Emperor angelfish need plenty of oxygen, so this will ensure their survival.

Aquarium Plants

Emperor angelfish do not harm plants. You may opt to use either genuine or fake plants in the tank to provide hiding places for your fish and enrichment for the aquarium environment.

Behavior and Compatibility

Emperor angelfish are territorial and aggressive. They will attack small fish that swim through their territory, so they are best kept in a single-species tank.

These fish often bully other species of angelfish as well as reef inhabitants, such as clownfish or anemones. Other peaceful nonaggressive bottom dwellers, including shrimp and snails, can coexist with emperor angels.

Emperor angelfish are migratory and spend most of their time searching for food throughout the aquarium.

How Many to Keep Together

Due to their temperament, Emperor angelfish are best kept alone, but it is possible to keep two or more together, if you tank is big enough.

NOTE: In larger groups, Emperor Angelfish can become more territorial and even more aggressive. To prevent these behaviors from becoming an issue, make sure that the tank is large enough to accommodate everyone.


Emperor angelfish are territorial and aggressive. They can be quite combative, especially in smaller tanks with limited space.

Aggression is usually targeted toward other fish of the same species or similar-shaped species. If you’d like to keep multiple emperor angelfish together, it’s best to do so in a tank that has ample room for each individual fish to claim its own territory.

Aggression can also be directed towards other aggressive fish.

Tank Mates

The best tank mates for the emperor angelfish are some of its closest relatives.

Other suitable choices are other butterflyfish, tangs, large wrasse varieties, six-line and eight-line wrasse, and damselfish (the blue zebra being one popular variety). Avoid any fish species with long fins like clownfish or anemonefish. They could be mistaken for food!

It’s always important to think about how much space each animal needs when choosing tank mates.

Here is a list of compatible tank mates for Emperor Angelfish:

  • Dottybacks
  • Six-line and 8-line wrasse
  • Damselfish
  • Tangs
  • Large wrasses
  • Butterflyfish
  • Sohal Tang
  • Blue Tang
  • Yellow Tang
  • Powder blue Tang
  • Brown Tang
  • Achilles Tang


Breeding emperor angelfish isn’t easy. It’s very difficult to breed these fish in captivity so we don’t recommend trying this.

Are Emperor Angelfish Fish a Good Choice For Your Tank?

Emperor angelfish are beautiful fish that will add a splash of color to your tank. However, they require very specific conditions in order to thrive and live long lives.

If you’re looking for an easy species to care for, these aren’t the fish for you. These coral-dwelling fish need plenty of space and pristine water quality if you want them to reach their full potential.

Not only that, but emperor angelfish can be aggressive towards other tank mates.


  • Emperor angelfish are breathtakingly beautiful fish that bring a splash of color to any tank.
  • This species can thrive in captivity but they do require some work. Compared to some other saltwater marine life though, they are relatively low-maintenance.
  • They’re relatively easy to find in the trade. Due to their availability, you can get one without too much hassle.


  • The biggest issue with keeping an emperor angelfish in your home aquarium is the territorial nature and aggression that these fish exhibit. They can be very aggressive against other fish.
  • They require a stable saltwater tank, which is quite difficult for beginners.


As you can see, emperor angelfish are an interesting species that require a lot of attention and care.

However, if you’re someone who wants something completely different from your tank (and don’t mind the extra work), this fish is definitely worth considering. All we ever hear are good things about them from aquarists who have them.

Leave a Comment