The Regal Angelfish is a fascinating fish and one of the most attractive angels in the ocean!

The Regal Angelfish Pygoplites diacanthus is one of the most striking angelfish to behold. It will reach around 9.8†in length and is adorned with white and orange stripes edged in blues and blacks. The dorsal and anal fins are striped in blue and orange, and the rear portion of the dorsal fin is black with blue spots. The tail is yellow and the fins are edged in a neon blue. These fish are wonderful to photograph in the wild, but unfortunately they are very difficult to keep and rarely survive in the home aquarium.

There are several variants in color form depending on place of origin, but all are equally distinctive. One is all yellow with white stripes. Another is solid yellow on the body with a few black spots on the belly and only a few blue lines on the dorsal fin. One of the most fascinating varieties has all white lines on the body creating what looks like a maze. Those from the Indian Ocean will have a yellow-orange head and breast while those from the Pacific will be a blue-gray in those areas. However most of these variations are rarely, if ever seen in captivity. Other descriptive common names are Royal Angelfish, Empress Angelfish, and Blue Banded Angelfish.

As delicate as it is exquisite, this striped beauty is best kept by expert aquarists with very large systems. It is difficult to care for, reluctant to feed, and is very shy and reclusive. The aquarium needs to be very large, at least 100 gallons or more, with lots of rockwork for hiding places to make it feel secure. The water quality must be pristine and have a pH of 8.1 or higher, as well as very stable temperature and salinity parameters. It is a finicky eater and needs sponge in its diet to survive. The ideal tank would be a reef setting with large established coral colonies. A very mature tank with lots of natural foods can help in long term survival. The best purchase size is 3†to 4†(7 – 10 cm) in length.

If you can get this angelfish to eat and if it adjusts, it will then become king of the tank. This is a very solitary species in the wild, they are rarely found in pairs. It is very timid in the aquarium, typically hiding from even semi-aggressive fish. Its tank mates need to be passive and it should be the first inhabitant added to the tank. It cannot be put in a tank with any other fish that may threaten it, including even a perceived threat. Once well established they become bolder. Combine it with other angelfish with caution. Some specimens have been known to actually attack and chase aggressive Pomacanthus angels that were added later to the tank. Adding two Regal Angelfish that are different sizes at the same time should only be done in a tank that is a minimum 180 gallons.

Because of these challenges, this a fish that will not be seen in many community aquariums. Its temperament could make it ideal for a reef environment, except it will pick as soft and stony corals, as well as zooanthids. Corals such as Xenia and Anthelia will be consumed. They will nip at some soft corals like Lemnalia and large polyped stony corals (LPS). Tridacnid clam mantles will be nipped at and they will eventually be killed. Only in very large systems with large coral colonies will the nipping not devastate the entire grouping, much like in the wild where large colonies are not affected by fish nibblers.

It’s very difficult to keep, but it is a beauty! If it acclimates and is happy with its environment, the end result is an exquisite fish that can live for 14 years or more. However for most of us, until collection methods are improved and husbandry knowledge reaches a point where we can help this fish survive long term, we should leave this beauty in its natural home.

For more Information on keeping saltwater fish see:
Marine Aquarium Basics: Guide to a Healthy Saltwater Aquarium

Paul Talbot talking about Regal Angelfish

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Regal Angelfish

Video shows Regal Angelfish being acclimated. Good commentary, suggesting buying corals to feed them and recommends against putting with angelfish, which is one of the few people who seem to get it!

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Perciformes
  • Family: Pomacanthidae
  • Genus: Pygoplites
  • Species: diacanthus
Regal Angelfish – Quick Aquarium Care
  • Aquarist Experience Level: Expert
  • Aquarium Hardiness: Difficult to Impossible
  • Minimum Tank Size: 100 gal (379 L)
  • Size of fish – inches: 9.8 inches (24.99 cm)
  • Temperament: Semi-aggressive
  • Temperature: 72.0 to 78.0° F (22.2 to 25.6&deg C)
  • Range ph: 8.1-8.4
  • Diet Type: Omnivore
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Habitat: Distribution / Background

The Regal Angelfish Pygoplites diacanthus was first described by Boddaert in 1772. They are found across a very large range in the Indo-Pacific; from the Red Sea, East Africa and Tuamoto Islands, then north to the Ryukyu and Ogasawara Islands, and then southward to the Great Barrier Reef and New Caledonia. Pygoplites is a monotypic genus, meaning this is the only species it contains. Like other marine angelfish, it was initially put in the Chaetodon genus, and older scientific names were Chaetodon diacanthus and Holacanthus diacanthus.

There are several color form variations, depending on place of origin. Those from the Indian Ocean will have a yellow-orange head and breast while those from the Pacific will be a blue-gray in those areas. These two may eventually be regarded as distinct species based on differences in color patterns and potential genetic differences.

This species is on the IUCN Red List as Least Concern (LC) as it has a large population with a wide distribution and there are no major threats currently identified. Other common names it is known by include Royal Angelfish, Blue Banded Angelfish, Empress Angelfish, Royal Empress Angel, and Royal Empress Angelfish.

These angels are found in coral rich clear lagoons and seaward reefs as well as reef channels, seaward reef faces, and fore-reef drop-offs near caves and ledges. They are reclusive and prefer rich coral areas with lots of holes and crevices, but with currents and moderate wave action. They are always on the move swimming from crevice to crevice in search of food. At times, they will swim with their belly toward the ceilings of caves. They are one of the more common Pomacanthids on the Great Barrier Reef.

They are most commonly found at depths between 3 – 157 feet (1 – 48 m), but at times small numbers can be found as deep as 262 feet (80 m). Juveniles occur solitary, and are very secretive and reluctant to emerge. Adults are usually seen alone or in pairs, and sometimes in harems that are typically one male with two to four females. Adults primarily feed on sponges and tunicates.

  • Scientific Name: Pygoplites diacanthus
  • Social Grouping: Varies – Adults are solitary or seen in pairs, and uncommonly in harems of one male with two to four females. Juveniles are solitary.
  • IUCN Red List: LC – Least Concern – A stable population.


Regal Angelfish from the Red Sea and Indian Ocean have a bright orange color on their ventral area and under the mouth. Indo-Pacific have a bluish gray color in this area. Juveniles do not show a clear distinction until they are larger. The basic color is yellow to orange with white angled vertical bars trimmed in black and blue which reach into the front part of the dorsal fin, while the back of the dorsal fin is solid blue. The tail, pectoral and pelvic fins are all yellow to orange (same color as the body) and the anal fin is striped in blue and yellow to orange.

In some variations, the blue and black in the coloration is missing, resulting in a yellow body with white stripes! The anal fin in this variation is white and orange or darker yellow than the body. The upper back of the dorsal fin is missing the blue, and has clear and yellow mottling. One wild and crazy color patterned Regal Angelfish was found in Papua New Guinea, where the white striping looks more like a squiggly road map.

Juveniles have a fake “eye†spot at the base of the back part of their dorsal fin, and have wider yet fewer white bars trimmed in blue. This false eye spot fades by the time the fish is 2.25†to 2.75†(6 – 7 cm) which is very soon compared to most angelfish. Other genus of angelfish do not reach their adult coloring until several inches larger. The dorsal fin, near the back is not blue like the adult.

  • Size of fish – inches: 9.8 inches (24.99 cm)
  • Lifespan: 15 years – The longest recorded lifespan for this angelfish in captivity is 15 years.

Fish Keeping Difficulty

These fish are difficult to impossible to keep alive long term and are suggested only for expert aquarists. They are very difficult to care for, reluctant to feed, and are very shy and reclusive. If they do not receive a varied diet and enough natural foods they will eventually starve to death. A very large tank, over 100 gallons, with mature live rock and producing copious amounts of tunicates and sponges as well as multiple hiding places is ideal. Adding this fish as a first addition to your tank can prove beneficial as it is very timid. It has been stated that bright light will deter them from coming out into the open for long periods of time, so provide ledges for them to hide under.

Proper size and health are the most important purchasing requirements. Obtain them at 3†– 4†(7 – 10 cm) since small ones will typically starve by the time they reach the the retailer,while older specimens ship poorly and don’t usually adjust to aquarium foods. Acquire one from the Red Sea or Indian ocean, thosesporting the orange neck and belly, since handling practices may be better. Before purchasing check for “pinching†or a concave look at the area above and behind their head. This is a starvation condition that they rarely recover from, even if they start eating. Make sure it will eat some brine or frozen mysis at the retailers. If a fish is hovering near the top of the water, itching, scratching or breathing heavily it will be a poor selection.

Quarantining is essential, with the QT tank being at least 20 gallons with a some PVC creating hiding places. Refugium aquariums work best for this delicate fish since it will naturally have good water quality and some natural foods. Keep the environment as stress-free as possible with little to no foot traffic near the tank. Cover the sides of the tank if your angelfish is not coming out. After 4 to 6 weeks, if there are no infections or parasites, then release it into the main aquarium.

  • Aquarium Hardiness: Difficult to Impossible – The proper diet, tank size, and tank mates will make or break the success in keeping a Regal Angelfish.
  • Aquarist Experience Level: Expert – These fish are difficult to impossible to keep alive long term and are suggested only for expert aquarists.

Foods and Feeding

The Regal Angelfish is an omnivore that feeds primarily on sponges and tunicates in the wild. In the aquarium feed a varied diet. Food like red nori seaweed (Seaweed Selects from Ocean Nutrition), marine algae, mysis shrimp and chopped krill work well. Other foods can include vegetables like spinach, husked peas, and lettuce (frozen and thawed to make it mushy). Freeze dried meaty foods can also be offered, and can be soaked in vitamins or garlic for fish. There are varying opinions on gel-based frozen foods. Remove any uneaten food so as to not spoil the water quality. There are several good commercial foods available as well, including Formula II and Angel Formula.

These fish are very timid and typically refuse to eat initially, but within a few days they should be out nibbling. Feed a variety of foods several times a day once they start eating. One aquarist had success (in a 500 gallon tank) with the red dried algae formed into rolls and adhered it to a rock with a rubber band or clip. Others have had success with opening live clams or mussels and offeringlive mysis shrimp to prompt a feeding response.

  • Diet Type: Omnivore – Sponge and tunicates are their main foods in the wild. Typically flake and tablets do not have the needed nutrition to be used regularly.
  • Flake Food: Occasionally
  • Tablet / Pellet: Occasionally
  • Live foods (fishes, shrimps, worms): Some of Diet – Live mysis may help start feeding response, as well as clams which are relished by angelfish
  • Vegetable Food: Most of Diet – They eat sponge material more than anything else. Marine algae, frozen lettuce (thawed), Nori, peas and other vegetables should be offered.
  • Meaty Food: Some of Diet – Live opened clams, meat left on shell, and freeze dried mysis and brine shrimp can supplement their diet, but should be used sparingly.
  • Feeding Frequency: Several feedings per day

Aquarium Care

Regal Angelfish are very sensitive to water quality, more so than other angelfish. Excellent water parameters are key in helping to keep this angelfish healthy. Doing weekly water changes may be necessary to keep nitrates very low. A water change of 10% a week is suggested for a 100 gallon tank, less in very large systems over 150 gallons.

As with all angelfish, keeping the pH at 8.1 to 8.4 is ideal. The pH should never drop below 8.1. Controlling pH levels is best resolved by water changes rather than chemicals. Using testing equipment is suggested to tell you when to do a water change.

  • Water Changes: Weekly – Suggested water changes of 10% weekly for a 100 gallon tank, with less needed for aquariums of 150 gallons or larger .

Aquarium Setup

Juveniles Regal Angelfish can be kept in a mature 50 gallon tank (190 l), while an adult needs 100 gallons (379 l) or more. Larger tanks over 100 gallons provide more stability in water quality and parameters which are essential for its well being. Water quality must be kept high and a pH of at least 8.1 is necessary.

This angelfish is timid and needs several places to hide in a live rock aquascape. Form crevices and caves in a way that they can hide and feel secure and unseen. Having several overhangs to shelter it from the light is also recommended. The live rock should have plenty of naturally growing tunicates and sponge. A reef tank is actually an essential element to the survival of this angelfish. Although they will pick on a few corals, their longevity is linked to such a system.

  • Minimum Tank Size: 100 gal (379 L) – Juveniles can be kept in a 50 gallon tank, but adults will need 100 gallons or more.
  • Suitable for Nano Tank: No
  • Live Rock Requirement: Typical Plus Hiding Places – This very timid fish which needs plenty of places to hide.
  • Substrate Type: Any
  • Lighting Needs: Moderate – normal lighting – They do not come out as much in tanks that are very bright, so provide some shading in the form of overhanging ledges in the rockwork.
  • Temperature: 72.0 to 78.0° F (22.2 to 25.6&deg C)
  • Specific gravity: 1.023-1.025 SG
  • Range ph: 8.1-8.4
  • Brackish: No
  • Water Movement: Any
  • Water Region: Middle – Will spend most of their time in the middle and lower portions of the aquarium.

Social Behaviors

The Regal Angelfish is semi-aggressive but should not be house with fish larger or faster than it is, especially in the beginning. Once it is feeding and well established, after about a year, other semi-aggressive fish may be added. Just make sure the angelfish doesn’t become stressed and stop eating. It can be aggressive with other types of angelfish and should not be kept with triggers, large wrasses, or quick feeding planktivores. Avoid dwarf angelfish unless the tank is hundreds of gallons in size as they will harass this angel. They can be kept with others of their same kind in tanks 180 gallons or more, but they should be added at the same time and be of different sizes.

These fish do best in a reef tank. Those who have been successful with Regals typically have tanks around 500 gallons that provide its natural foods. That large tank sizekeeps any one coral from being picked on too much andthe fish in these large systems are typically well fed.

  • Venomous: No
  • Temperament: Semi-aggressive – Should not be house with larger or faster species, especially in the beginning. In a larger reef tanks with lots of corals, if it is well fed it shouldn’t do too much damage.
  • Compatible with:
    • Same species – conspecifics: Yes – They can be kept with their own kind In a tank over 180 gallons. Make sure they are different sizes and added at the same time.
    • Peaceful fish (gobies, dartfish, assessors, fairy wrasses): Safe
    • Semi-Aggressive (anthias, clownfish, dwarf angels): Monitor – Do not house with dwarf angelfish unless the tank is hundreds of gallons and only once the Regal Angelfish is well established.
    • Safe – They should be added after the Regal Angelfish is established, eating and healthy for a long time. Any stress can prevent the Regal from adjusting and eating well.
    • Large Semi-Aggressive (tangs, large angels, large wrasses): Threat – These fish will over compete for food and stress the Regal Angelfish out, resulting in not eating, leading to starvation and death. Once established, eating and healthy for a good year, adding one of these fish may work.
    • Large Aggressive, Predatory (lionfish, groupers, soapfish): Threat – Do not house with fish larger than your Regal Angelfish.
    • Monitor – Mandarins may be fine in larger reef systems.
    • Anemones: Monitor – In a larger tank with lots of corals, and if it is well fed, the Regal Angelfish shouldn’t do too much damage. Plus if they are protected by clownfish, they should be fine.
    • Mushroom Anemones – Corallimorphs: Monitor – In a larger tank with lots of corals, and if it is well fed, the Regal Angelfish shouldn’t do too much damage.
    • LPS corals: Monitor – Typically safe, but has been known to pick at LPS. In larger tanks it shouldn’t pose too much of a threat if well fed, especially if there is an abundance of of these corals.
    • SPS corals: Monitor
    • Gorgonians, Sea Fans: Monitor
    • Leather Corals: Monitor
    • Soft Corals (xenias, tree corals): Threat – Should be safe with the more noxious soft corals. The tank size and an abundance of food are key factors.
    • Star Polyps, Organ Pipe Coral: Threat
    • Zoanthids – Button Polyps, Sea Mats: Monitor
    • Sponges, Tunicates: Threat
    • Shrimps, Crabs, Snails: Safe
    • Starfish: Safe
    • Feather Dusters, Bristle Worms, Flatworms: Monitor
    • Clams, Scallops, Oysters: Threat
    • Copepods, Amphipods, Mini Brittle Stars: Safe

Sex: Sexual differences

Sexual differences are not discernible, though it is possible that males are slightly larger. Those born female have the ability to change to male.

Breeding / Reproduction

Has not been bred in the aquarium, nor has it been cultivated in any laboratory as of yet. In the wild, the mating dance begins about 15 minutes before the sun sets and up to 25 minutes afterward. The female, when she is ready to spawn, will rise up off the bottom and extend their pelvic fins to the males. The males will then get behind the female and nuzzle her belly with his nose. He nuzzles her belly in a perpendicular fashion (“T†shape), which is not a typical angelfish posture. They will rise upward in a spiral until they are about 1 to 3 feet off the bottom (.3 to 1 m). The female will then release her gametes, after which, the male will release his and will thrust his tail upward and create a vortex that shoots the fertilized eggs toward the surface, which ends up being around 30 feet (9 m). This is thought to protect them from the local egg eating zooplanktivores.

  • Ease of Breeding: Difficult

Fish Diseases

The most common ailment is for thiis angelfish is starvation. Do not buy a Regal Angelfish if the upper back of the head (when viewing head-on) is at all sunken. Even if the fish is eating, it is too late for that specimen and it will not likely recover. Like other saltwater angelfish they are prone to any disease that captive saltwater environments have to offer. They are most likely to be affected if they are stressed from inappropriate housing or tank mates. Providing an angelfish with clean water, a proper decor with places to hide, and regular feeding is the best way to prevent illness. Calm angelfish are healthy fish. If not stressed, they will have a stronger immune system to prevent infections. To avoid a condition called nutritional blindness in angelfish, which can occur around 6 to 8 months after taken into captivity, feed green leafy foods that have Vitamin A, as well as making sure there is plenty of natural occurring algae in the tank.

White Spot Disease Cryptocaryon irritans, also known as Marine Ich, Saltwater Ich, or Crypt is the most common disease that is generally associated with marine tangs and angelfish. Symptoms of Marine Ick are constant scratching, culminating with lots of white dots. These dots disappear for a few days, only to return with double the number. This results in the fish suffocating from these parasites blocking the gills from providing oxygen.

Another common disease is Marine Velvet or Velvet Disease Oodinium ocellatum, (syn: Amyloodinium ocellatum or Branchiophilus maris), which is a parasitic skin flagellate. Symptoms of Marine Velvet are a peppery coating giving a yellow to light brown “dust” on body, clamped fins, respiratory distress (breathing hard as seen as frequent or quick gill movements), cloudiness of eyes, glancing off decor or substrate, and possible weight loss.

A viral infection, Lymphocystis, looks like small cauliflower-shaped nodules on the fins and mouth. These nodules are not harmful and come and go. The only time action may be needed is if they were on the mouth area of the fish, preventing it from eating for a prolonged period of time. It’s best to do water changes to help the fish’s natural immune system kick in.

Monogenetic flukes are the most common parasitic infections angelfish are prone to contracting. Parasites on marine fish kept with live rock or in any type of reef environment can be extremely difficult to treat. Typical treatments like copper and formalin solutions, as well as quinine based drugs are harmful to other marine creatures. However drugs such as metronidazole provide an effective and safe treatment for several protozoan and anaerobic bacterial diseases. Metronidazole works by ceasing the growth of bacteria and protozoa. Metronidazole is an antibiotic for anaerobic bacteria with anti-protozoal properties. This drug is reef safe, and medications are either added to the water or mixed with the fish food. Some available products that contain metronidazole include Seachem Metronidazole, Seachem AquaZole, Thomas Laboratories’ Fish Zole and National Fish Pharmaceutical’s Metro-Pro.

For external parasites you can slowly increasing the temperature of your tank to at least 82° F (28° C). That will prevent the parasite from completing its life cycle which includes the attachment to fish. A further combination of the higher temperatures with medicated food will provide timely relief.The Seachem Metronidazole medications works well in combination with another Seachem product called Focus, which is a bonding agent. This treatment can be used in a reef aquarium since the medication is bound to the food, which even if the corals eat, will not hurt them. Mix Focus in a ratio of 5 to 1 with their Metronidazole (5 parts Focus to one part Metro), then mix this with 1 tablespoon of food. Feed the medicated food to the fish 3 times a day for at least a week or until symptoms are gone.

Fish problems can be broken into one of (or a combination of) these types: parasites, bacterial disease, fungal disease, or physical ailments caused from deficiencies in diet as well as wounds and injuries. For more information on diseases that saltwater angelfish are susceptible to, see Aquarium Fish Diseases and Treatments.


These fish can be found online and in stores. They are at times seasonal and are quite expensive. Opt for a 3-4†specimen from the Red Sea or Indian Ocean rather than the Indo-Pacific, as those from the Indo-Pacific have a poorer life expectancy.


Pez ángel real (Pygoplites diacanthus) (Image Credit: Diego Delso, Wikimedia Commons CC BY-SA 4.0 International)