Emperor Angelfish

Emperor Angelfish 

The Emperor Angelfish is one of the most delicate and brightly colored angelfish, and it is frequently the highlight of any aquarium.

While many people believe that emperor angelfish is one of the hardest angel fish types to keep, as they require a large saltwater tank size and rigorous water parameters, it’s easier than you might think.

In this guide, we will go through all you need to know about emperor angelfish, from their original habitat to tank requirements and dietary demands.


Common NamesThe emperor angelfish, The Imperial Angelfish
Scientific NamePomacanthus Imperator
AggressionSemi-aggressive fish
LengthUp to 12 inches
BreedingNo successful captive breeding
Ease of CareModerately hardy
Minimum Tank Size175 gallons
Temperature72-28 F (22-25 C)
Emperor angelfish characteristics table

The Origin & Habitat of the Emperor Angelfish

The Emperor angelfish (The Imperial Angelfish) was first identified in 1787 and given the scientific name of Pomacanthus Imperator.

The Pomacanthus imperator is a ray-finned fish belonging to the Actinopterygii class, the order of Perciformes, and the colorful family of Pomacentridae.

The name of the genus is derived from the Greek terms “poma” = cover, which refers to the operculum’s spine, and “akantha” = spine, which alludes to the operculum’s spines.

The species name “Imperator” comes from the Latin word for “emperor,” owing to its magnificent appearance.

Where Do Emperor Angelfish Live?

Emperor angelfish are known to reside in the warmer waters of the Atlantic, Indian, and Pacific Oceans. However, they can also be found in the Red Sea, Hawaii, and Australia.

Emperor angelfish have also been spotted off of New Caledonia as well as Florida-Puerto Rico!

The recent sightings suggest that these fish may have recently colonized the Mediterranean shores via the Suez Canal—no doubt coming over like some invader intent on taking what’s ours!

However, it’s not uncommon for such magnificent fish: Many individuals from various populations across oceans seem to be capable of developing such colonial tendencies when they find themselves stranded together by storms at the red sea.

Juveniles live alone and are mostly found under ledges or in holes of semi-protected channels. 

Emperor angelfish can also be seen on outer lagoon reefs or reef flats, but these last two locations may not offer enough cover from predators for this type of fish to survive for very long periods.

For this reason, you can mainly find them near secluded channels with enough protection from larger predators.

Whereas sub-adults can be seen swimming through channels and caves, they are hidden under ledges along the reef frontlines and on seaward reefs. They usually live at a depth of 1 to 80 meters (3-262 ft).

Emperor Angelfish Size

The size of an Emperor Angelfish can range from 1-3” (2.5–7 cm) in its juvenile stage to 3-4” (7.6–11cm) for sub-adults and 12 inches long when mature.

Emperor Angelfish Life Cycle and Lifespan


1. Fry

The angelfish eggs will hatch in approximately 60 hours at 80° F. After that, the fry go into the “wiggler” stage, which lasts about five more days.

During the wiggler stage, the fry will feed on their egg yolk until they’re free-swimmers.

2. Juveniles

It takes up to two years for the juvenile emperor angelfish to become an adult emperor angelfish.

During these two years, the juvenile lives alone, hiding out in reefs or holes while growing larger and stronger before entering their next form of adulthood.

3. Adults

Once it gets into adulthood, it becomes a little more confident and starts to take territories and brutally defend it against invaders.


One of the many advantages of imperial angelfish is its long lifespan.

It’s one of the longest-lived species in captivity, with a typical lifespan of up to 20 years, and they tend to live even longer in the wild!

Emperor Angelfish

Emperor Angelfish Appearance

The Emperor angelfish goes through three distinct phases (juvenile, sub-adult, and adult) and undergoes various physical changes as they mature. Not only in size but also in color.


In fact, until 1933, the juvenile was considered a distinct species, known as Pomacanthus Nicobariensis.

A juvenile Emperor angelfish has a black body with bright blue and white vertical stripes on its face, with three broad white curved bands around it.

The first curve extends from the dorsal fin to the anal fin; the second band forms a “C” shape, and the third is a tiny white circle near the tail fin.

Between each thick white curve are thinner light blue curves. The black hexagonal markings on the dorsal and anal fins are complemented by light blue edging. A white border surrounds the dorsal fin.


The sub-adult emperor angelfish is similar in appearance to the juvenile, but you’ll notice that its tail fin has developed a yellow pattern and vertical lines on the body; it also becomes deeper and rounder.


The adult emperor angelfish is deep-bodied with yellow and blue striped lines that run horizontally across its body from the gill area to the beginning of the yellow tail fin.

The dorsal fin has a white edging. It also features an intimidating mask-like black band across its eyes, which is outlined with blue trimming and gives this predatory fish’s face some much-needed color to make it stand out against the dark abyss surrounding them in their natural habitat.

Emperor Angelfish

Author note:

Don’t be fooled by Emperor Angelfish’s resemblance to the Koran (Semicircle) Angelfish, Pomacanthus semicircular, which is somewhat similar.

The very last white stripe might form a circle on a Koran juvenile. On the other hand, the Imperator juvenile has a complete circle within the “C” shape.

Additionally, the Koran does not have irregular light blue-lined circles in the dorsal and anal fins, unlike the Imperator Angelfish.

Is Emperor Angelfish hardy?

The Pomacanthus imperator is a saltwater fish that needs moderate care.

These aquatic creatures require specific water conditions to keep them alive and happy. Still, they can often be hard to maintain for the average hobbyist due to their size and the space needed, which is usually quite extensive.

Also, these creatures do not travel well or handle stress very well, making them prone to illness when transferred between tanks by aquarists who aren’t aware of how delicate they are.

How Much Do Emperor Angelfish Cost?

Tiny: up to 1.5″ in length$129.99
Small: over 1.5-2″ in length$149.99
Medium: over 2-3″ in length$159.99
Large: Over 3-4.5″ in length$199.99
Emperor angelfish cost table

Emperor Angelfish Care

Water Requirements

1. pH Level

Emperor angelfish are found in soft, slightly acidic water consistently warm throughout the year.

To be honest, we’ve had minimal to no difficulty raising angelfish in water with a pH ranging from 4.7 to 8.7, and we’ve handled everything from very soft to extremely hard water. However, 8.1 to 8.4 is the sweet spot.

If your water isn’t within this range. If it is extremely hard or alkaline, a de-ionization filter or reverse osmosis (RO) filter can help bring it to an acceptable level.

RO filters generally connect to your main water supply and transform tap water into distilled water. 

2. Temperature

Your aquarium water temperature should be somewhere in the range of 80° to 84° F.

We’ve seen angelfish spawn in water temperatures as low as 60 °F and as high as 90 °F, but we think you should avoid extremes. 

Low temperatures are associated with fewer spawns and a higher risk of disease. 

On the other hand, extreme temperatures induce bacteria growth and prematurely age the angelfish, as their oxygen-carrying capacity is decreased.

3. Water changes

Water changes regularly will eliminate extra dissolved organics and other poisons that build up without them. We recommend changing 40% of your aquarium water weekly.

Tank Set-Up

1. Tank Size

The space required by Emperor Angelfish is one of the most difficult aspects. If you wish to keep a single Emperor Angelfish, your saltwater tank must be at least 125 gallons.

However, if you want to house a pair, it should be at least 175 gallons for juvenile Emperor Angelfish.

In adulthood, on the other hand, the tank capacity may reach 220 gallons. 

2. Decoration

Emperor Angelfish prefer areas with a lot of sluggish water and hiding places such as roots and tall plants.

Live rocks are the ultimate way to keep Emperor Angelfish happy. If you can find some, get your hands on some and give it a try!

However, be aware that these fish love nothing more than biting at their rock, so make sure the cave doesn’t have any pointy cones or sharp edges, as this might harm your pet. 

Hiding spots are also essential for ensuring they are comfortable in the wild, as they spend most of their time hiding in coral reefs and rocks. Attempt to arrange the boulders in a way that allows them to hide within them.

3. Lighting

Emperor Angelfish require adequate and bright light to survive. It will not only aid in the coloration process, but it will also aid in the prevention of head and lateral line erosion illnesses. We suggest reef-like lighting since it will mimic their natural surroundings.

4. Filter

Emperor angelfish are voracious eaters, which would induce a significant bi-load that contains ammonia and nitrites.

Ammonia and nitrites are toxic to angelfish. They can’t keep up with the high levels of pollutants in the water. A good filter will assist in the removal of these poisons. 

Our favorite is an aquarium sponge filter since they are the most cost-effective.

They are also beneficial since they create little noise and turbulence, which is required when caring for angelfish.

Emperor Angelfish Care

Emperor Angelfish Compatibility 

Emperor angelfish is a social fish, but its needs are different when kept in captivity. Because the small space will never replicate what it experiences in the wild, no matter how big your tank is, these lovely creatures turn defensive and even territorial towards their kind during feeding time due to stress caused by being confined for so long.

Suitable TankmatesUnsuitable Tankmates
DamselsLarge Angels
SquirrelfishLive Corals
Emperor angelfish suitable and unsuitable tank mates

Emperor Angelfish Diet

Emperor angelfish are naturally omnivorous, feeding on plants and small invertebrates. Their primary diet consists of algae and sponges, but you need to provide them with vitamin-rich food that will help with their coloration issues!

You can give these colorful fish, meats, or vegetables plus any sponge material for additional nutrients until you find out what works best, depending on individual needs. 

What Does Emperor Angelfish Eat?

The diet of an Emperor angelfish should include the following items:

  • Marine Algae
  • Spirulina
  • Dried Flake
  • Frozen Meaty Food
  • Cockles
  • Scallop
  • Brine Shrimp
  • Mussels
  • Squid
  • Spinach
  • Tunicate
  • Hydroid
  • Bryozoan
  • Krill
  • Mysis

They become aggressive fish while eating, and if they believe there isn’t enough food in the tank, they may attack the other fish. Therefore, ensure enough food for everyone in the tank at all times.

Make sure you’re only feeding them enough to keep their bellies full. Overfeeding is one of the most common causes of poor water quality. We recommend feeding them two or three times daily in modest amounts.

Emperor Angelfish Gender Difference

Adult male and female Emperor Angelfish have subtle color differences. The males will have a darker shade behind their eyes, whereas the females will be less bright overall.

Males are also generally somewhat larger than adult females. Still, it’s extremely difficult to tell the sexes apart without having a sexually mature male and female side by side. 

Emperor Angelfish Breeding

Breeding Emperor Angelfish in captivity is very difficult. It’s possible to breed these fish if you have a large enough tank and provide them with specific conditions, but breeding at home is nearly impossible due to their high requirements for water temperature and pH levels.

Emperor Angelfish lays eggs once a year. They spawn throughout August and September in the Marshall Islands. 

Males maintain a harem of two or more females, each having her own territory.

It’s conceivable that, like other Pomacanthus, they ascend in the water column, circle one another, and release their sperm and eggs simultaneously at the top of their accent.

The larvae float for a few weeks before developing into fry. When males descend from spawning, they are known to “grunt.”

Is Emperor Angelfish Reef Safe?

They nip anemones, soft corals, zoanthids, Large Polyp Stony Corals (LPS), and clams, making them hazardous to marine life. However, if your fish are properly fed, they will not attack them so is the emperor angelfish reef safe the answer is yes.

Emperor Angelfish Disease Potential

Unfortunately, Emperor angelfish are at risk of experiencing several diseases. Ich, Marine Velvet, and Head & Lateral Line Erosion Disease are the most common. All three can be deadly if not treated correctly!

If you’ve ever kept tropical or marine fish, you’re familiar with Ich! This illness is caused by an external parasite known as White Spot Disease. It’s highly contagious and deadly if left untreated.

Marine velvet is a parasitic disease that causes the fish’s skin to be covered with gold-colored dots when infected. It’s named after the fabric because it resembles velvet.

Finally, Hole-in-Head Disease (HLLE), or Head and Lateral Line Erosion Disease, is a condition in which a fish’s head and lateral lines get holes.

The precise reason for this illness isn’t known, but it is thought that giving Emperor Angelfish too much light may contribute to its occurrence.

The easiest way to avoid all these conditions is to keep an eye on the tank. Maintaining optimum conditions and keeping your fish happy may help you prevent major medical concerns.

Last Words.

The Emperor Angelfish is a beautiful and highly ornamental fish that will make an excellent addition to any saltwater aquarium. This species requires special care, as it can be difficult for beginners with these types of tanks; however, if you’re experienced enough then adding one into your collection should not pose many difficulties!

You should maintain proper water conditions, and be able to keep them in a large tank.

We hope you have enjoyed this guide as much as we did.

Do you have any questions? If so, please let us know in the comment section below.