Emperor Angelfish (Pomacanthus Imperator): Ultimate Care Guide

Common NameEmperor Angelfish
Scientific NamePomacanthus Imperator
OriginIndian and Pacific Ocean
Temperature72°F – 82°F
Water pH8.1 – 8.4
Size12 inches

Emperor Angelfish Facts

  • Emperor Angelfish juveniles have different markings than their mature counterparts. Mature Emperor Angelfish develop their characteristic yellow and blue stripes on their bodies.
  • Emperor Angelfish are the only fish that have yellow and blue stripes.
  • Emperor Angelfish has a rather large tank size requirement at 220 gallons for just a single fish.
  • Emperor Angelfish are not bred in captivity due to how difficult it is to provide them with enough space and the right conditions.
Emperor Angelfish (Pomacanthus Imperator)
Emperor Angelfish (Pomacanthus Imperator)

Emperor Angelfish appear differently as juveniles than they do as fully mature fish. The juvenile Emperor Angelfish have more curved, horizontal bands of white, black, and blue, whereas mature Emperor Angelfish have yellow and blue horizontal stripes on their bodies. They are popular fish for home aquariums for their beauty, and coloration as no other fish has yellow and blue stripes.

Emperor Angelfish have large, boxy shaped bodies, with smaller mouths and small eyes. They have small, bright yellow tails. They have a dark blue band across their eyes, and they have black on their underside.

Emperor Angelfish Care

Emperor Angelfish are not easy fish to care for, and they are not recommended for beginners to the fishkeeping hobby. They are not as forgiving of incorrect water parameters, and they will quickly become ill if they are not kept in the correct conditions.

Emperor Angelfish also requires a large amount of space at 220 gallons for a single adult fish. They are territorial and aggressive towards other fish. It is best to place them in a tank with lots of places for them to swim and hide. It is important that they are kept in a stress free environment so that they do not develop illness.

Tank Requirements (Tank Size, Temperature, Water pH)

Emperor Angelfish are considered a difficult fish to care for. Partly because of all they require to keep happy, and partly because if their needs are not met or their water parameters are off, then they will not do well and fall ill quickly.

Emperor Angelfish requires a large tank that is at least 220 gallons or larger, and has live rock for them to graze upon. They also require lots of caves and rock to hide in as well. They can do well in a reef tank setup, but beware what kind of coral you keep them with as they will eat LPS.

For water parameters, Emperor Angelfish prefer their temperature to be around 72F to 82F, and 8.1 to 8.4 pH. Juvenile Emperor Angelfish lives among the rocks and caves near the reef, but as they get older they spend most of their time near the reef.

Food & Diet

Emperor Angelfish are omnivorous, opportunistic feeders, and it is important to feed them a varied diet of both plant and animal matter to make sure that their dietary needs are being met. Emperor Angelfish will readily accept flaked and pelleted foods as well as dried seaweed, scallops, and spirulina.

Emperor Angelfish should be fed only enough food that they can completely consume in roughly 5 mins, and you will want to clean the food bits they leave behind up so that your water stays clean.

Emperor Angelfish Size & Lifespan

Emperor Angelfish can grow up to 12 inches in length in captivity, and can live around 18 years. In the wild, Emperor Angelfish grows to be longer, and live longer. Their health and longevity is directly dependent on how well they are kept.

Tank Setup

Setting up a tank for Emperor Angelfish is the hard part of their care. You have to first make sure that you are starting out with a tank that is large enough. For juvenile Emperor Angelfish, you can get away with housing them in a smaller tank, but they will quickly outgrow it.

When setting up a tank for Emperor Angelfish you will want to set up a habitat for them that closely resembles their natural habitat in the wild. They enjoy a planted tank with lots of room to swim about freely. They prefer lots of light. A good quality, bright light is recommended as it helps bring out their bright coloration as well as helps keep them from getting sick.

Emperor Angelfish like live rock so that they can forage on algae, and have plenty of places to hide and destress. A strong filtration system is a good idea as they have to have the correct pH to survive, and angelfish are messy eaters. You will want to make sure to remove any uneaten bits of food so that they do not dirty their tank.

Are Emperor Angelfish Reef Safe?

Emperor Angelfish are not reef-safe even though they are found around coral habitats in the wild. Since they are omnivorous and opportunistic feeders, they will happily seize the opportunity to dine on LPS corals. There are types of corals they will not consume, like bubble corals, but finding the right coral can be tricky as they will devour a coral in no time.

Emperor Angelfish Breeding

Emperor Angelfish are not bred in the home aquarium because of the massive amount of space they require to do so. A single Emperor Angelfish requires at least 220 gallons, and that is already a large aquarium. Currently, they have not been successfully bred in the home aquarium.

How Do Emperor Angelfish Breed?

When Emperor Angelfish are ready to spawn, they rise to the surface of the water, release and fertilize their eggs together, and the eggs slowly drift downward onto the reef where the lucky ones will land in a safe place until they hatch.

How Do You Tell the Difference Between Emperor Angelfish Males and Females?

The easiest way to tell the difference between male and female Emperor Angelfish is by the colorations they display when they are fully mature. It is almost difficult to perceive unless you have both a male and female together. Fully mature female Emperor Angelfish tend to be less vibrant than the males, and if you look at the coloration behind their eyes, males will have a less dull appearance.

Juvenile Emperor Angelfish

Emperor Angelfish juveniles are easier to care for as they do not require as much space as fully mature Emperor Angelfish do. As they grow, they require more space, and their colors will change. Juvenile Emperor Angelfish are a completely different color than their mature counterparts, but just as strikingly beautiful. Juvenile Emperor Angelfish have blue, white, and black curved, horizontal stripes. Fully mature Emperor Angelfish have blue and yellow horizontal stripes.

Juvenile Emperor Angelfish
Juvenile Emperor Angelfish

Emperor Angelfish Color Change

When Emperor Angelfish are juveniles, they display a completely different coloration than they do when they are fully mature. Juveniles have bended horizontal stripes of blue, white, and black. When they reach full maturity, their stripes change into blue and yellow.

Emperor Angelfish Disease

Emperor Angelfish are not recommended for beginners to the fish keeping hobby due to how much care and space they require to keep happy. They are susceptible to illness if there is even a slight shift in their water parameters. If your Emperor Angelfish doesn’t seem like it is thriving or is exhibiting any changes in behavior or diet, then the first place you should look is at their aquarium and how they are being kept. Keep in mind that stressed fish will become ill quickly, and Emperor Angelfish are quick to stress if they are not being kept in the appropriate sized aquarium.

Emperor Angelfish are prone to getting quite a few diseases. The most common ailments that can affect your Emperor Angelfish are:


Ich is a parasitic infection, also commonly called white spot disease. It is called this because it shows up on the scales of the fish in white blotches that will grow to take over the whole fish if left untreated, eventually causing the death of the fish. Ich can be treated if caught early.

Marine Velvet

Marine Velvet is another parasitic disease that can affect your Emperor Angelfish. It shows up as a goldish colored blotch on the skin that has a velvety-like appearance. This is where it gets its name. Just like with Ich, Marine Velvet is curable as long as it is caught early on.

Hole in the Head Disease

Hole in the Head Disease is also known as Head and Lateral Line Erosion Disease or HLLE. This disease can affect fish that are being kept in poor conditions. It makes the skin of the fish appear to be rotting and flaking away. Fish can recover from this illness, but it does cause permanent scarring.

Most of these ailments are caused by fish not being kept in the appropriate conditions. It is better to try and prevent illness from happening than it is to cure it. Emperor Angelfish requires clean water, and correct water parameters to thrive. It is recommended that you do 10% water changes if you are keeping your Emperor Angelfish in a reef tank setup.

Emperor Angelfish Tank Mates

Emperor Angelfish are territorial and aggressive. They do best when added last to a community setup so that they do not become too territorial. However, depriving them of space is not the solution to being able to house them in a community setup. They require a lot of space, and if you are going to keep a pair together, then they will require even more space.

Some owners of Emperor Angelfish say that they have been able to keep them in their community tank setup with no issues at all, but this behavior seems to vary depending on the fish and how well they are kept, but Emperor Angelfish do not do well with other angelfish, or fish of similar shape and color.

You can keep a male and female Emperor Angelfish together, and even two females with one male. You should never keep two males together. Examples of good tank mates for the Emperor Angelfish are smaller and more aggressive fish such as wrasse, dottybacks, and damselfish.

Emperor Angelfish males should not be kept together. If you want to keep more than one in your aquarium, you would do best to choose 1 male and 1 female or multiple females.

Are Emperor Angelfish Aggressive?

Emperor Angelfish are an aggressive and territorial species. Two males should not be kept together. If you are wanting to place them into a community tank setup, you would have the best success when adding them to the community tank last so that they do not claim a territory and defend it from other fish. They require a large amount of space to keep them happy, and if you are planning on adding them to a community tank, you must take that into consideration. If they are not kept with enough swimming space, or hiding places, they will stress quickly and become ill.

In the wild, male Emperor Angelfish will claim territory and live with a harem of females. They defend their territory from other males. It is for this reason they do not get along with other Angelfish or other fish of similar size and coloration.

Emperor Angelfish and Clownfish

Emperor Angelfish and Clownfish can be kept together successfully in a community tank setup, but you need to keep in mind their size difference. Emperor Angelfish are a large species of fish, and they are slightly aggressive over space, and they may not want to share their space with the much smaller Clownfish and chase them away. Clownfish would do better with a smaller species of Angelfish.

Where Can I Find Emperor Angelfish For Sale?

If you are looking to purchase Emperor Angelfish for your home aquarium, you can find them for sale online, and at most pet stores. A juvenile Emperor Angelfish costs around $130, and goes up from there depending on the size of the fish.