Annularis Angelfish

The Annularis Angelfish (Blue Ring) is a spectacular fish to add to any large aquarium.

These fish have a lovely dark orange color and a magnificent bright white caudal fin, and annularis angelfish was formerly classified as butterflyfish due to their compressed bodies and butterfly features.

In this guide, you’ll learn all you need to know about keeping and caring for Annularis Angelfish in your home aquarium.


Scientific NamePomacanthus annularis
SpeciesPomacanthus annularis
Common NameBlue Ring Angelfish, Annularis Angelfish, Blue King Angelfish
Care LevelDifficult
SizeUp to 18 inches (45 cm), most get up to about 12 inches (30 cm)
Lifespan15 – 20 years, possibly longer
Temperature72°F – 76°F (22°C – 24°C) 
pHdKH 8 – 12
Specific Gravity1.020 – 1.025 
OriginEast Africa, Indo West Pacific, Indonesia, New Guinea, New Caledonia, Southern Japan.
Tank Size180 gallon (680 liters) minimum
BehaviorShy at first, get more semi aggressive growing up
Annularis Angelfish Characteristics

Annularis Angelfish Origin & Habitat


Pomacanthus annularis is a tropical South Pacific fish that may be found in Sri Lanka south to the Solomon Islands and from the Philippines to northern Australia.

This range is generally defined as 25 degrees north to 25 degrees south.

Pomacanthus annularis may also be found in the Indo-West Pacific oceans from East Africa throughout Indonesia and New Guinea to New Caledonia and north to southern Japan.



The adults typically dwell at 5-15 meters in their natural settings, although blue ring angelfish may descend as low as 30 meters.

Blue ring angelfish are most commonly spotted alone or in twos in caves on the rocky/coral oceanic bottom.


The juveniles are often at the top of the water column in coral reefs and lagoons, but blue ring angelfish will also descend to the bottom when threatened.

Annularis Angelfish Behavior

Annularis Angelfish Behavior
Annularis Angelfish Behavior

As with other members of the genus Pomacanthus, these angelfish dwell in harems and are ruled by a male that monopolizes five females.

The size of this space might range from the size of a bathroom to that of a two-car garage.

These species are protogynous hermaphrodites, meaning blue ring angelfish can change sex from female to male in a single-sex environment.

At the start of life, all youngsters are females. When a dominant male dies, the largest female changes sex and becomes the new male.

This transformation can also happen when a juvenile male is displaced from the harem by a larger male.

Juveniles thrive in water as shallow as 6 to 10 inches deep, with rocky or dead coral substrates and short filamentous algae. Adults mostly eat zooplankton, sponges, filaments, and tunicates.

Blue ring angelfish might be quiet at first, but after acclimating to the tank, blue ring angelfish should settle in with other angelfish. Young Blue-Ringed angelfish are violent, but annularis angelfish become semi aggressive as annularis angelfish get older.

Annularis  Angelfish Characteristics

Annularis  Angelfish Characteristics
Annularis  Angelfish Characteristics

1. Appearance

Until recently, members of the family Pomacanthidae were classified together with butterflyfishes because blue ring angelfish possessed “common characteristics such as deep compressed bodies, ctenoid scales that extend out along the median fins, and a tiny mouth with brush-like teeth.”

The spines on the corner of the preopercle are longer than those on butterflyfishes, but blue ring angelfish differ from them in having smaller spines on the preopercle, opercle, and preorbital).

Besides, the dorsal fin has 13 spines and 20-21 soft rays, while the anal fin has three spines and 20 soft rays.

2. Color


The adult has a yellowish-brown body with numerous minute dots and about eight oblique blue lines that run lengthwise on the side.

The face is blue with blue lines just behind the eyes, and there is a yellowish-brown area surrounding the eye encircled by blue.

The blackish thread in the middle of the dorsal fin fades to yellowish behind. In contrast, the caudal fin is white and fades to darker shades on the margin, the pectoral fins are golden yellow with a blue-black spot at the fin base, and the pelvic fins are golden yellow with numerous blue-black lines.


Blue ring angelfish are blackish-blue with numerous vertical white and blue bands on the side, which get more numerous as annularis angelfish grow. Annularis angelfish have bluish-black tails with a translucent to the whitish caudal fin.

3. Length

This species can grow to a maximum overall length of 45 cm (18 in).

Adults usually reach 17.6 inches (45 cm) in length. However, the most available specimens in pet stores are less than 8 inches (20 cm).

4. Lifespan

Annularis Angelfish can live for up to 16 years in captivity with appropriate treatment. However, some large angelfish, such as the P. annularis, have lived up to 25 years in captivity.

Annularis Angelfish Availability

The Blue-ring Angelfish is available at pet stores or may be purchased online, and blue ring angelfish is relatively expensive.

Medium: over 2.5-4.5″$399.99
Large: over 4.5-6.5″$549.99
X-Large: over 6.5-7.5″$599.99
XX-Large: over 7.5-8.5″$649.99
Show: over 8.5-10.5″$699.99
Annularis Angelfish Availability

Is Annularis Angelfish Hardy?

Blue ring angelfish is moderately hardy if maintained in an appropriate tank with many hiding places and suitable tank mates.

Stocking a tank that is too small can lead to stunted growth, which might harm the fish’s organs and muscle development and reduce its lifespan.

In general, you should avoid tanks that are less than 135 gallons, even for juveniles; 250 to 300 is the appropriate size to keep them healthy.

How to Care for Annularis Angelfish?

How to Care for Annularis Angelfish
How to Care for Annularis Angelfish

1. Water Parameters

Water Changes

The Blue-ringed Angelfish is sensitive to changes in water chemistry and needs clean, well-oxygenated water.

Water changes of 20% a month, or 10% every two weeks, are acceptable if the aquarium has a lot of fish and the tank is big.

Also, be careful about significant water changes since pomacanthus annularis can cause the fish to go into shock.


The Blue-ringed Angelfish lives in tropical waters where the temperature is between 72 and 82 degrees F (22 and 28 degrees C).

We discovered that the ideal temperature range for keeping them healthy is between 72.0 and 76.0 degrees Fahrenheit (22.2 and 24 degrees Celsius.

pH Level

The pH level is another crucial factor in keeping this fish healthy; a pH of 8.1 – 8.4 is recommended.

Ammonia, Nitrite & Nitrate

Ammonia levels should always be 0 ppm, as any detectable level will quickly kill a fish.

The same goes with Nitrite levels, it should also be 0 ppm, as even a trace amount can poison the fish.

On the other hand, Nitrate levels can be kept between 10 and 40 ppm without harming the fish. However, keeping it below 20 ppm is recommended, as higher can lead to algae growth and reduced water quality.

2. Tank Setup

The Best Tank Size For Blue Ring Angelfish
The Best Tank Size For Blue Ring Angelfish

Minimum Tank Size

A 135-gallon tank is an absolute minimum for a single P. annularis, with larger being better.

These fish are fiercely territorial, so a big tank will help deflect some of their hate away from other fish and make it simpler to hide.

If you have a male/female tank mates pair, we recommend housing them in 250 to 300 gallons of water.

Lighting Needs

Annularis Angelfish is the wild that depends on sunlight to break down vitamins from the foods blue king angelfish consume to help them absorb those nutrients.

So, you must provide them with moderate-standard lighting since a tank with dim lighting may result in several issues, including blindness.

The moderate-lighting environment will not only mimic their natural habitat but will also aid in the development of naturally growing foods on live rock.


These species are susceptible to skin and lateral line diseases, so it is important to use a good quality filter that can handle a large aquarium.

A canister filter with a foam pad and ceramic grid is the best option for these fish since it will provide plenty of surface agitation.

Sponge filters, on the other hand, are not advised for this fish.

Hiding Places

Angelfish enjoy rock work that has been set up to provide several hiding places while also giving open swimming areas.

Also, young fish when blue king angelfish is first introduced to the tank may spend a lot of time hiding.

So, provide plenty of caves and overhangs for them to use until blue king angelfish feel comfortable in their new surroundings.

Annularis Angelfish Diet

Annularis Angelfish Diet
Annularis Angelfish Diet

Diet Type

The Blue-ringed angelfish Pomacanthus annularis are omnivores feeding on benthic invertebrates such as

  • Zooplankton
  • Sponges
  • Tunicates
  • Coral polyps
  • Ascidians
  • Algae
  • Weeds
  • Nektonic fishes
  • Brine shrimp
  • Nori flakes
  • Thawed mysis brine shrimp
  • Spirulina
  • Color-enhancing foods, such as carrots and beets may also be incorporated.

Feeding Frequency

Feeding Frequency is a significant factor in keeping these fish healthy and their coloration.

Many hobbyists overfeed their fish, resulting in the accumulation of waste and pollutants in the aquarium, which can lead to health issues.

Therefore, it is essential that you feed your Blue-ringed angelfish two or three times a day, only what annularis angelfish will eat within a five-minute.

For juveniles, you can feed them smaller amounts more often, about four times a day.

Annularis Angelfish Compatibility

The angelfish is a popular aquarium fish, and it can be kept with certain semi aggressive species, making choosing tank mates easy.

Also, smaller fish such as cardinalfish, gobies, tilefish, butterflyfish, fairy basslets, fairy and flasher wrasses can be excellent choices.

The following table summarizes the annularis angelfish compatibility in further detail:

Same SpeciesMonitorAnnularis angelfish can sometimes be semi aggressive toward other angelfish unless the system is massive, which is generally around 250 – 300 gallons. Annularis angelfish may be kept as a male/female pair or in with another angelfish of a different hue and size in a large tank.
Peaceful Fish (Gobies, Gartfish, Assessors, Fairy wrasses)ThreatMay harm small delicate fish. Most Pomacanthus are okay with these species, but the Blue-ringed Angelfish is an exception.
Semi-Aggressive (Anthias, Clownfish, Dwarf angels)MonitorProvide many hiding places for these fish and watch for aggressiveness.
Aggressive (Dottybacks, 6-line & 8-line Wrasse, Damselfish)SafeThese fish can usually be kept with the annularis without any problems.
Large Semi Aggressive (Tangs, Large Angels, Large Wrasses)
Larger angels, such as the orange or white dwarf angel, may pick on slower-moving sharks and stingrays.
Large Aggressive, Predatory (Lionfish, Groupers, Soapfish)SafeThese fish will usually leave the angelfish alone.
Slow Swimmers & Eaters (Seahorses, Pipefish, Mandarins)ThreatIf individuals cannot obtain certain fish, annularis angelfish may be harassed or picked on.
AnemonesSafeMaroon Clownfish are usually peaceful, but semi aggressive Maroon Clownfish or other aggressive clowns like Cinnamon, etc., may solve the problem.
Mushroom Anemones – CorallimorphsSafeThese anemones will not harm the angelfish.
LPS Corals
May harm coral.
SPS coralsMonitor Many individuals have had success with them but pay attention to personal preferences.
Gorgonians, Sea Fans
Leather CoralsMonitor These corals do well with the annularis but should not be placed near stinging corals.
Soft Corals (xenias, tree corals)MonitorMany growers have had excellent outcomes with those from the Sinularia, Sarcophytom, Cladiella, and Paralemnalia genera but continue to monitor individual responses.
Star Polyps, Organ Pipe CoralThreat
Zoanthids – Button Polyps, Sea Mats
Sponges, Tunicates
Brine shrimp, Crabs, SnailsMonitorTiny brine shrimp, such as Sexy mysis shrimp, maybe in danger.
StarfishMonitorIf not fed, annularis angelfish will go after the appendages.
Feather Dusters, Bristle Worms, FlatwormsMonitorIf not fed, annularis angelfish may nip at feather dusters.
Clams, Scallops, OystersThreat
Copepods, Amphipods, Mini Brittle Stars
Even though the Blue-Ringed Angelfish will consume these things, their populations should not diminish in the wake of its arrival.
Annularis Angelfish Compatibility

Are Annularis Angelfish Reef Safe?

Pomacanthus Annularis Good Reef Dweller
Pomacanthus Annularis Good Reef Dweller

The Blue-ringed Angelfish is not a 100% reef-safe species, even though it will flourish in an environment with sessile invertebrates.

Annularis Angelfish will chop off the polyps of both hard and soft corals and sessile invertebrates such as mysis shrimp.

Several individuals have reported that the fish may be kept with small polyped stony (SPS) corals, but it will eat the polyps of gorgonians, xenia, athelia, and zoanthids.

Also, annularis angelfish may attack Polypodium (LPS) corals except for clams, oysters, scallops, feather dusters, and sessile invertebrates.

This species is considered protogynous hermaphrodites, meaning it starts out as females.

When the time comes for them to reproduce, the larger species will change into males.

Annularis Angelfish Breeding

The spawning process starts when the male begins his courtship dance that ends with the male and female swimming toward the water’s surface, where annularis angelfish release their eggs and sperm.

Then, after a month, the eggs will hatch and the larvae will feed on zooplankton.

The larvae will then undergo a metamorphosis, turning into juveniles. It takes about six to nine months for the juveniles to reach sexual maturity.

Note: It has been suggested that only one male and one female can mate at a time, but males may also engage in polygyny with multiple females within the colony.

Annularis Angelfish Diseases and Treatment

Pomacanthus Annularis Diseases and Treatment
Pomacanthus Annularis Diseases and Treatment

Annularis Angelfish are sensitive to saltwater, so annularis angelfish are susceptible to saltwater-disease disorders if annularis angelfish are not kept in a healthy environment.

This angelfish may suffer from:

White Spot Disease (Marine Ich, Saltwater Ich, or Crypt)

Cryptocaryon irritans are the cause of this condition. This manifests as a fish’s constant scratching, culminating in white spots on its skin.

The expanding and contracting white spots on the fish are not just scary; annularis angelfish is also dangerous.

These parasites block the gills from providing oxygen, causing the fish to suffocate.

Symptoms of White Spot

  • White spots on the body
  • fish scratching itself constantly
  • loss of appetite
  • weight loss.

Marine Velvet Disease

Marine Velvet or Amyloodinium ocellatum is a parasitic dinoflagellate that can quickly kill an aquarium fish.

The protozoan attaches to the fish’s skin and gills and takes control of the cells, reproducing rapidly.

Symptoms of Marine Velvet

  • The peppery coating gives a yellow to light brown “dust” on the body
  • Clamped fins
  • Respiratory distress (breathing hard as seen as frequent or quick gill movements)
  • Cloudiness of eyes
  • Glancing off decor or substrate
  • Possible weight loss.

How to Prevent These Diseases

  • Make sure you use a good quality salt mix and follow the manufacturer’s instructions.
  • Keep your tank clean by performing water changes and vacuuming the gravel regularly.
  • Quarantine new fish for at least two weeks before adding them to your main tank.
  • Provide your fish with a healthy varied diet and keep the tank’s temperature stable.

Last Words

Annularis Angelfish are a beautiful addition to any aquarium, and with the proper care, annularis angelfish can thrive in both saltwater and freshwater tanks.

Be sure to acclimate your angelfish properly before adding them to your tank and provide plenty of hiding places for juveniles.

Also, watch out for saltwater-disease disorders, and keep a close eye on your angelfish to ensure annularis angelfish stay healthy and happy.

We hope you have enjoyed this article as much as we did.

Please share any questions with us in the comment section below if you still have any.