Emperor Angelfish Care Guide | The Aquarium Guide

Emperor Angelfish Care Guide | The Aquarium Guide


Perhaps the most interesting thing about the emperor angelfish pomacanthus imperator is their appearance. Some inexperienced aquarists may believe that there are different species of emperor angelfish, but they will be surprised to learn that the angelfish emperor pomacanthus imperator they see is actually the same one. This species evolves drastically in appearance during each life stage.

They are classified into three stages: juvenile emperor angelfish, sub adult angelfish and adult angelfish.


How big do emperor angelfish get? The emperor angelfish pomacanthus imperator can be as large as 15 inches in the wild. However, like most other fish, in captivity they are a bit smaller, getting up to about 12 inches.


They are known to display bright hues of yellow, dark blue, white, black and a bit of indigo. Of course, this all depends on their life stage. Let’s take a closer look at these amazing changes.

Juvenile emperor angelfish are the most beautiful in our opinion. They sport cold colors and have a vertical lines and wavy patters on their bodies and faces. Their base color is dark blue or black with light blue and white stripes. The emperor angelfish juvenile will also have what looks like spots on the dorsal to anal fins.

Once they get slightly older and mature to sub adults, you can see a yellow hue start to develop on their tail fin. This yellow will slowly creep onto their bodies to slowly transform them into the adult form. The once curved bands on their body will also slowly change and take shape into stripes across its body.

Adult emperor angelfish pomacanthus imperator will have yellow and blue stripes across its body with a fully yellow tail fin. It will also have a predominantly white face with a dark blue or black band across its eyes and other dark blue markings.

Since you can almost say that a fish’s development in captivity is stunted, all this color-changing will take longer than it would in the wild. Also, the coloration of captive emperor angelfish pomacanthus imperator are less vivid in captivity, but that can be solved with color brighteners.


You will be pleased to know that the emperor angelfish has a very long lifespan of over 20 years in the wild! In captivity, this number is lessened to 15-18 years. Since they do come with quite a high price tag (even though they are common in the aquarium trade), they are a good investment since they can keep you company for a long time.


As mentioned, the emperor angelfish isn’t the easiest to take care of, and this is partly due to their pickiness in diet. When you first introduce your emperor angelfish to your new tank, chances are it will not want to eat. However, as it acclimates to the environment, things will get better. You need to give it the chance to forage for its own food.

Make sure they have enough to eat when they are first welcomed to their new home. Feeding sessions up to 5 times a day may be necessary. The actual food they are willing to eat is quite easy to handle because they are omnivores (both plant and meat diet), they have a more diverse diet.

Just make sure you feed them a good and balanced meal that consists of veggies, meat and sponge materials. Their diet in the wild is exceedingly difficult to mimic in captivity, and the best you can do is to mix tunicates, hydroids with algae. They are a cleaner fish, so they can take care of the algae aspect on their own.

Feeding sponge materials can rack up the price of the emperor angelfish, so a good substitute would be a steady supply of live and frozen foods. Think about veggies and shrimps 5 times a day. When your emperor angelfish get better adjusted to the new surroundings, you can decrease feeding to about 3 times a day.

Consider a balanced diet including all or most of the following:

  • Algae
  • Flake food
  • Brine shrimp
  • Squid
  • Mussels
  • Spinach
  • Hydroid
  • Krill
  • Mysis

When they feed, the emperor angelfish also has a tendency to become more aggressive. Since you need to feed them so many times when they are first introduced, it’s important to make sure there is enough food to go around. This way, they will have less of a chance to be aggressive if there is enough to be had.

Overfeeding your emperor angelfish is also a risk. To find out just how much to give them, watch how much food they can finish within a 5 min time frame or even less. This will be a good gauge for how much they need, and then you will just have to factor in the portions for the other species.

Make sure that you clean up after them. The number one reason for soiled water quality is leftover food that isn’t properly removed. As mentioned, although they aren’t as vividly hued as they would be in the wild, a symptom of a poor diet include faded colors.


The emperor angelfish is Pomacanthidae family and is a saltwater fish found in tropical waters all over the world.

Tank Conditions

Since they are found in many parts of the world, you would think that an emperor angelfish can tough out different water conditions. However, they are surprisingly less hardy than a lot of other saltwater species. Another interesting point about emperor angelfish is they seem to be three different fish rolled into one.

Aside from their distinct color changes throughout their maturing phase, they also change their habitats as well. Juvenile emperor angelfish can be found in rocks near the reef but the sub adults move closer into the reefs. When they mature into full-fledged adults, they gravitate more towards coral. Make sure you include lots of rockwork when decorating your aquarium.

It is always recommended to raise your angelfish from the juvenile (mostly blue) stage. This will give them enough time to adjust to aquarium life, and to acclimate to food in captivity. Another feature that this species requires is adequate sunlight. In order for them to be 100% healthy, place the tank in an area with sufficient light. This will actually decrease the chances of diseases and help their coloration as well.

Because they eat a lot, they have a large bioload. For this reason, we suggest purchasing a reliable water filter. Not only will this filter be responsible for keeping the water clean, it will also produce slow currents that the angelfish is used to. Plants can be kept in the tank but although they are used to reefs in the wild, we don’t recommend them in the aquarium and this is because they will start nipping at them.


The temperature of the aquarium is best kept at 72-82oF (22-28oC), as they are more accustomed to warmer waters.

Water Conditions

The water quality should be maintained quite precisely. The emperor angelfish will thrive with a  pH of 8.1-8.4 (more alkaline) and a gravity of 1.023-1.025. Keep the water slow-flowing or still just like their regular environment.

Minimum Tank Size

To give them the best chance in captivity, you need to do your best to replicate their natural environment. They are used to having lots of space and can be territorial, so you’re looking at a minimum aquarium size of 125 gallons for just one emperor angelfish and over 180 gallons for a pair.

Maintenance and Care

They need to be introduced into established aquariums, so you need to have the tank set up way before you bring your angelfish home. It also needs to be completely cycled and you should clean the water regularly. It needs to be done as often as once per week or every two weeks slowly. Starting from 10-15% with the same amount being cycled every time.

They are a beautiful fish, but the emperor angelfish does require a more than average amount of your attention to thrive in captivity.

Suitable Tank Mates

Keeping one emperor angelfish per tank is recommended, but we understand if most people cannot resist the beauty of these exotic fish. In this case, having 2 is suggested but you would need a lot of room as a 180 gallon tank is the minimum for a pair. If you do get a pair, we suggest getting a male and female as males are less aggressive towards their counterparts if they are of the opposite sex.

Do not keep smaller fish with them as they can be subject to their bullying and anything small enough that can fit into an emperor angelfish’s mouth is considered to be food. The fish you place with this exotic species should not resemble them in color or shape. Other than different angelfish, the pomacanthus imperator doesn’t take well with ones that are similar to it.

The best tank mates would be smaller (but not by too much) and aggressive fish or larger semi-aggressive fish. Some suitable aquarium buddies for the pomacanthus imperator include:


To minimize territorial behavior from the angelfish, introduce them to the tank last. That way, it will make it seem as though all the territories have been claimed by other species first. This will definitely make the emperor angelfish more humble and less aggressive.


As for breeding, there has yet to be a successful one to be recorded in captivity. Unfortunately, if you plan on breeding your emperor angelfish, you may be in over your head. They are surface spawners, which can be hard for them to do in captivity. This is to give their spawn the best chance at survival when their eggs are scattered all over. They usually spawn once a year, and it takes the eggs about 2 weeks to develop into fry.

You can distinguish the male from female due to a small difference in their coloration. Females are less colorful and vibrant and the males are slightly larger.


If you keep a saltwater aquarium and would love to add a bit of color and exoticness to your tank, the emperor angelfish is an amazing candidate. However, since they are not the easiest to care for, we would dissuade beginner aquarists to attempt to raise them.

You need a lot of space and a lot of care to make sure your emperor angelfish will thrive in the aquarium and they are much less forgiving with changes in water conditions. Since they should be the last ones to grace your tank, you need to do extra research into which fish would be compatible tank mates before purchasing one.

Aside from the price tag, a lot of effort in caring, and the space you would need, emperor angelfish are quite the trophy inhabitants of a tank for an aquarist.

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