Regal Angelfish (Pygoplites diacanthus)

Pygoplites diacanthus, sub-adult, Egypt
zsispeo/Flickr/CC BY-SA 2.0

Of all the fishes in the ocean, the Regal Angelfish (Pygoplites diacanthus) is, without a doubt, among the most beautiful. Unfortunately, it is also among the most difficult for a novice aquarist to keep in an aquarium. However, given the proper attention to detail and an environment which caters to the Regal's specific needs, it can thrive in an aquarium for many years.


The Regal Angelfish can be found throughout the Northern and Western Indian Ocean, the Red Sea, and the Indo- Pacific Ocean.

The sex of the Regal angelfish cannot be determined by color variations; however, color differences do exist between specimens from the Red Sea and Indian Ocean versus those from the Indo-Pacific region. Red Sea/Indian Ocean specimens exhibit a bright orange coloration throughout the ventral area and under the mouth while those from the Indo-Pacific area are blue-gray. The difference is clear in adult specimens but somewhat harder to discern in juveniles. Juveniles have the same coloration as adults with the exception of a false eye-spot at the base of the dorsal fin. This spot disappears when the juvenile reaches about 3" in size.

Maximum Size

The Regal Angelfish attains a maximum length of about 10".


In the wild, the Regal Angelfish greatly prefers an area naturally rich in coral growth, both inside and outside the reef and at depths from knee deep down to 150'. This fish greatly prefers to stay near areas with plenty of cracks, crevices, and caves where it can quickly hide from any perceived threat.

The smaller the Regal, the closer it stays to concealing cover. The Regal Angel is usually found singly or in mated pairs or small groups with one male and several females.

Minimum Tank Size Suggested

Juvenile Regals will do fine in a 55g tank but will require a larger tank (100g or more) as they mature and grow larger.

Reef Tank Suitability

A reef-type aquarium is very much preferred by this fish as it provides the rocky reef structure that the fish requires to feel secure. Combining regal angelfish with corals is always risky, but they are generally "safer" than most other Pomacanthids and even most Centropyge species. If a regal is going to pick on corals, it is usually confined to a particular coral or type of coral. The choice for the aquarist is then between keeping the corals or the fish. Regals generally ignore species but have been reported to pick on certain large-polyped stony corals such as Trachyphyllia or certain soft coral such as Xenia. Regal angels that are well-fed are less likely to venture about the aquarium looking for another food source.

Characteristics and Compatibility

Regal Angels are definitely not aggressive fish and will not fare well with more aggressive or larger fish in the same tank. Other angelfish will become a problem when they outgrow the Regal. Placing two Regals in the same tank usually will not work well even if they are of the opposite sex (which it is almost impossible to determine) and the smaller one is placed in the tank first.

When purchasing a Regal Angelfish there are several "always" and several "nevers" to keep in mind.

Always have the seller show you that the regal is eating in the aquarium (preferably on several occasions)  before purchasing. Never buy a Regal that is on sale. It will normally be sub-par and not in good health. Always buy Regal Angels that are caught from either the Red Sea or the Indian Ocean, not the Indo-pacific as many of these fish are still captured using chemicals and will not survive long. The cost will be more, but the end product will be worth the extra expense.

It is wise to quarantine a new regal for several weeks before placing it in your show tank. Regals do not adapt easily to tank life and don't really need the added distractions of other fish when they are trying to figure out what is and is not safe to eat. Quarantine the new arrival in a 20g or larger tank (refugiums work well for this) until it is eating hand fed foods well and shows no signs of disease or parasites.

Smaller (juveniles of about 2-3" seem to adapt to tank life the easiest. They are too young to be set in their ways but old enough to have survived the threats they have faced.

Diet and Feeding

In the wild, Regals graze on benthic invertebrates with a particular fondness for sponges and tunicates. In captivity, this fish should be offered a variety of foods to ensure that all of the nutritional requirements are being met. While there are many opinions on what is the best food to offer the Regal, a varied diet consisting of food items such as red nori seaweed, Pro-V gelatin food, Mysis shrimp, and chopped krill has been reported to work very well for this fish. Pro-V is a frozen mix of seaweed and vegetables in a gelatin base. Simply cut a slice of the Pro-V from the sheet and place it in a food clip attached to the side of the tank.

The Regal Angelfish is not an aggressive feeder and does not fare well when competing with quick-feeding planktivores in a community aquarium. Choosing the proper tank mates for the Regal is imperative to its survival.


The Regal Angelfish has been reported to spawn at dusk or in the dark of the night. The female performs a spiraling dance as she releases her eggs for fertilization by the male. The eggs float to the surface where they join the other living matter in the plankton "soup" in the ocean. as with most other pelagic fish, very few aquarists have reported any success at all with breeding this fish in captivity.