Regal Angelfish
Pygoplites diacanthus
A breathtakingly beautiful marine angelfish known as the Regal Angelfish, notorious for its extreme dietary stubbornness in home aquaria.
Water Temperature
24 - 28 °C
pH Value
8.1 - 8.4
Water type
Freshwater
Tank level
All levels
Adult size
25 cm
Minimum tank volume
500 L
Minimum group
>= 1
GH
8 - 12 dGH
KH
4 - 6 dKH
TDS
160 - 240 ppm
Conductivity
250 - 375 uS/cm
Species description
Geographical Origin and Habitat: Distributed from the Indian Ocean (including the Red Sea) throughout the Pacific Ocean, including the Maldives, Great Barrier Reef, and Tahiti. Inhabits almost exclusively coral-rich slopes, exposed outer reefs, and clear lagoons, preferring very shallow waters abundant in caves (1-48 meters).
Taxonomy and Morphology: Regal Angelfish. The sole member of the genus Pygoplites. Medium size (maximum 25 cm / 10 inches). The body is highly compressed, less discoidal than the Emperor, and more oblong. Gill spine always present. It is considered among the most beautiful, graceful, yet delicate fish in the world.
Social Behavior: The most elusive, mild, and timid among the large pomacanthids. Lives a withdrawn life, perpetually sneaking and hiding in the maze of rocks. It will NEVER impose itself in the aquarium hierarchy, making it extremely vulnerable to stress if chased by tangs, triggerfish, or other angelfish, which will prevent it from feeding.
Coloration and Sexual Dimorphism: The livery "explodes" with color: bright yellow-orange background marked by sharp vertical stripes of pure white, edged with black lines, resembling a colorful zebra. The lower part of the anal fin is covered in concentric neon blue horizontal stripes. Red Sea specimens have a bright yellow throat and chest (more prized and robust); Indo-Pacific ones have a white-gray chest.
Care, breeding and tankmates
Aquarium Setup: Aquarium of at least 500 liters (130 gallons), dedicated solely to calm and peaceful fish. The abundance of high-quality, porous live rock to graze on in peace is vital. The tank must offer constant shaded areas. Avoid voracious tankmates (like dominant damselfish) that would terrify it.
Diet and Feeding: The real trial for the keeper: it is an almost exclusive spongivore (sponges and tunicates). In the aquarium, it very often REFUSES commercial food and starves to death in 3 weeks. It is crucial to attempt acclimation by forcing fresh clams opened on the half-shell, live mysis, masago (fish roe), and specific frozen sponge-based angelfish preparations.
Water Quality: Intolerant of any kind of pollution or pH drop. Pristine oceanic parameters are mandatory: pH 8.2-8.4, specific gravity 1.025, temperature 24-27°C (75-81°F). Once settled and eating (which can take weeks), it becomes surprisingly long-lived.
Compatibility and Cohabitation: Considered the "Most Reef Safe" Angelfish among the large formats. Although in rare cases it might nip Zoanthids or clams, it almost always ignores most hard SPS and LPS corals. To be paired exclusively with submissive and peaceful species (Anthias, small Gobies, Blennies, and small wrasses).
Aquarium Breeding: Impossible in private aquariums. In the wild, forms harems with one male and several females that court at dusk with ascending dances, releasing pelagic eggs that hatch as plankton. Commercial stock relies entirely on wild capture.
Risks and Diseases: Has one of the highest post-capture mortality rates in the aquarium hobby (food refusal). It is essential to demand seeing the fish EATING AVIDLY in the store before purchase. Very sensitive to copper medication, preferring the use of chloroquine in case of infections (Ich, Velvet).
Geographic Origin and Distribution
Distributed from the Indian Ocean (including the Red Sea) throughout the Pacific Ocean, including the Maldives, Great Barrier Reef, and Tahiti. Inhabits almost exclusively coral-rich slopes, exposed outer reefs, and clear lagoons, preferring very shallow waters abundant in caves (1-48 meters).
Origin
Tropical oceans and reefsEurope, Mediterranean, and West AsiaSouth and Southeast Asia
Fish profile
- Temperament
- Semi-aggressive
- They are notoriously shy and skittish when first introduced. Once acclimated, they become incredibly bold and active display fish. They possess a graceful, deliberate swimming style that is mesmerizing.
- Diet
- Omnivore
- They are specialized omnivores requiring sponges and tunicates in their diet. High-quality marine angelfish preparations containing sponge matter are essential. Finely chopped fresh seafood helps supplement their complex nutritional needs.
- Life expectancy
- 10-15 years
- The Regal Angelfish has a lifespan in the aquarium of approximately 10 to 15 years, although many imported specimens suffer from acclimation stress that drastically reduces their initial longevity. It is a demanding species that requires a mature system, perfect marine parameters, and a very specific diet. Providing a stable environment free of aggressive tankmates is crucial to supporting their biological resilience in the long term.
- Adult size
- 25 cm
- The catalog's scalar value is 25 cm. The FishBase SPECIES table (v25.04 snapshot) source reports a maximum adult measurement of 25 cm for this species, recorded as standard length (SL). The taxonomic record consulted is Pygoplites diacanthus (v25.04); male or unsexed record. These figures are not interchangeable: the first is the profile's editorial reference, whereas the second is a published maximum under a specific measurement convention; differences among sources can reflect sex, population, life stage and measuring method.
- Sex ratio
- Solitary
- Keeping a single specimen is the safest and most common practice. Mated pairs can be kept only in exceptionally large display aquariums. Putting two males together will result in immediate, fatal combat.
- Feeding frequency
- Twice daily
- They require feeding multiple times a day with small portions. They are naturally constant grazers on live rock in the wild. Frequent feeding helps divert their attention away from picking at corals.
- Bioload
- This stunning marine Angelfish creates a moderate to high bioload. A highly mature reef system with an oversized skimmer is mandatory. Pristine water quality is absolutely critical for their long-term survival.
- Flow
- Stagnant
- They enjoy moderate to strong water flow simulating reef environments. Powerful wavemakers ensure the water is highly oxygenated and clear. Good flow also helps flush debris from their extensive rockwork territories.
- Reproduction
- Oviparous
- Breeding them in home aquariums is considered virtually impossible currently. They are pelagic spawners that release eggs into the open ocean column. Larval rearing requires specialized facilities and microscopic marine plankton.
- Compatibility & tankmates
- They are semi-aggressive and generally peaceful towards dissimilar species. They may nip at fleshy large-polyp stony corals and clam mantles. Do not house them with other large, aggressive marine angelfish.
- Tank level
- All levels
- They utilize every available level of the aquarium's rockwork. They constantly weave in and out of caves looking for food. They require massive amounts of live rock to feel secure.
Scientific Parameters & Models
FishBase
Window to the official scientific data of the species
Data synced on: 06/15/2026
- Trophic level
- 2.7 ± 0 se
- Resilience
- Low (4.5 - 14 years)
- Phylogenetic uniqueness (PD50)
- 1
- Bayesian Length-Weight
- a = 0.0302, b = 2.89
- VulnerabilityLow vulnerability (21 / 100)
Image gallery
Licensed images linked to the species or, when marked, to the closest representative taxon.
Related species
Recommendations grouped by close relatives, companion choices, and similar care.























































