The flashy Blue Damselfish is a brilliantly colored small damsel, but with a big attitude!

The Blue Devil Damselfish Chrysiptera cyanea is an enduring favorite of saltwater aquarists. A lively fish sparkling with a rich sapphire blue coloring and a bold personality, it brings the aquarium to life. It only grows to about 3 1/3 inches (8.5 cm) in length, but many folks like the purity and beauty of this brightly colored fish. It is one of the most popular of the damselfishes.

This species is dichromatic, with distinct color differences between the adult male and female. Those available in a pet store may often be juveniles that have not yet come into their adult coloration. As they mature, males originating from across most of their natural habitat, develop yellow-orange tail colors and sometimes yellow on the nose. Those males originating from Japan and the Philippines, however, are all blue with dark margins on the fins. Females are similar, being the same bright blue, but they gain a black spot at the base of the hindmost dorsal ray and the fins are clear. These fish are known by a number of descriptive common names that reflect both their color and behavior including Blue Damselfish, Blue Devil, Sapphire Devil, Sky-blue Damsel, Blue Demoiselle, and Orangetail Damselfish.

This is one of several bright blue damselfish found in the Chrysiptera genus. One close relative that has a similar coloration, and is also known as a “devil,” is the Fiji Blue Devil DamselfishChrysiptera taupou. The biggest difference between the two is really in name only. The Fiji Blue Devil has a band of yellow color extending along the entire lower portion of its body, which is absent on the Blue Devil. However the Fiji Blue Devil is much more aggressive. In fact it is the most aggressive damselfish in the entire genus, so you really don’t want to get them mixed up.

The Blue Damselfish are inexpensive and very hardy, making them a great choice for both the beginning aquarist or the more advanced. They make a beautiful addition to a fish only aquarium and they are also a nice additon to a reef tank. As they mature, damselfish in generally are noted for becoming rather aggressive. The juveniles and females of this species are usually not overly aggressive but larger males can be very belligerent, especially with more peaceful fish like gobies, blennies, cardinalfish, firefish, and the like. They are great for a reef aquarium as they won’t bother any coral or invertebrates, but a large male will limit the types of other fish that can be kept.

These fish can be kept singly or as a pair in a 30 gallon tank, but they are best not kept with smaller or overly passive tank mates. They can be kept in a group if you are careful to have a good male to female ratio and keep a close eye out for trouble. One male with several females can work in a medium or large tank, as long as there are lots of hiding places. Providing a rock or coral decor that has many nooks and crannies for hiding and retreat will help avert aggression.

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

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Perciformes
  • Family: Pomacentridae
  • Genus: Chrysiptera
  • Species: cyanea
Blue Devil Damsel – Quick Aquarium Care
  • Aquarist Experience Level: Beginner
  • Aquarium Hardiness: Very Hardy
  • Minimum Tank Size: 30 gal (114 L)
  • Size of fish – inches: 3.4 inches (8.51 cm)
  • Temperament: Aggressive
  • Temperature: 72.0 to 84.0° F (22.2 to 28.9&deg C)
  • Range ph: 8.1-8.4
  • Diet Type: Omnivore
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Habitat: Distribution / Background

The Blue Devil Damselfish Chrysiptera cyanea was described by Quoy & Gaimard in 1825. They are found throughout the Indo-West Pacific region; the eastern edge of the Indian Ocean, Western Australia to New Guinea on the northern portion of the Great Barrier Reef, Solomon, Mariana, and Caroline Islands, Indonesia, Philippines, Taiwan and Ryukyu Islands. They are also reported from Vanuatu and New Caledonia; Palau and Yap in Micronesia. This species is not listed on the IUCN Red List of Threatened Species.

They have several additional common names with most relating to their coloring and their personality. Other names they are known by include Blue Damselfish, Blue Devil, Sapphire Devil, Sky-blue Damsel, Blue Demoiselle, Orangetail Damselfish, Orangetail Blue Damselfish, Cornflower Sergeant Major, Red tail Australian Damsel, Devilfish, and Hedley’s Damselfish.

About the Chrysiptera Genus:

This species is a member of the very large Pomacentridae family of Damselfish and Anemonefish. It belongs to the subfamily Pomacentrinae in the large Chrysiptera genus. There are currently 34 recognized species in this genus.

Some Chrysiptera species occur at rather deep reef zones, but the majority are found in the shallower waters of lagoons, sheltered bays, and coastal fringing reefs. They live near coral growth and may hover close to the substrate. They occur singly, in pairs, or in small loose groups. They are omnivores, feeding on plankton, algae, and small benthic crustaceans.

This genus contains some of the most beautiful and brightly colored damselfish, as well as some of the smallest. On average the species range about 2.8 inches (7 cm) in length to a few centimeters longer. They may be territorial towards conspecifics, but many are not as aggressive as other Pomacentrids towards other types of fish.

Their small size along with the less pugnacious nature of many of the Chrysiptera makes them suitable for the aquarium. Some of the more passive species can even be kept in groups and may get along with more peaceful tankmates. There are exceptions, however, as some species become highly aggressive in the confines of an aquarium as they mature.

About the Blue Devil Damselfish:

The Blue Damselfish inhabits clear sheltered lagoons, protected inshore reefs, and subtidal reef flats. They occur at depths between 1 to 33 feet (.03-10 m). They are typically found in groups among areas of coral rubble or live stony coral growth.

The Blue Devil damsels are typically seen in small to large groups consisting of one male with several females and juveniles. Sometimes groups will have more than one male, but the number of females greatly outnumbers the number of males. Mature males are very aggressive and typically have their territories close to a nesting site. They feed on filamentous algae, tiny crustaceans such as planktonic copepods and amphipods, and planktonic fish eggs.

  • Scientific Name: Chrysiptera cyanea
  • Social Grouping: Groups – This Chrysiptera species typically occurs in small to large groups.
  • IUCN Red List: NE – Not Evaluated or not listed


The Blue Damselfish is a rather elongated, deep bodied fish. These damselfishare moderately small in size, reaching up to about 3 1/3 inches (8.5 cm) in length. Similar to other damselfish, their life span in the wild is likely 2 to 6 years and they probably live the typical 15 years in captivity.

Blue Devil Damselfish (female) Chrysiptera cyanea
Blue Devil Damselfish, female Photo © Animal-World: Courtesy David Brough

The body of the Blue Devil is a bright sapphire blue and there is a dark stripe running through the eye and across the nose. The females will develop a black spot at the base of the hindmost dorsal ray and their fins are transparent.

This species is dichromatic, with distinct color differences between the adult male and female. There are also two distinct color morphs:

  • Blue Devils that originate from across most of their natural range are also known as the Orangetail Damselfish. The males develop yellow-orange tail colors as they mature, and some individuals will also have a yellow-orange snout.
    The amount of color on the male’s tail can increase or decrease depending how successful the male is at spawning. Those that attract the most females and have the most number of eggs in their nest tend to get more colorful tails while those that are less successful will have less color in the tail.
  • Blue Devil males that come from Japan and the Philippines are all blue with the males having dark margins on the fins.

This species is sometimes confused with its close relative, the Fiji Blue Devil Damselfish Chrysiptera taupou, because of their similar names. Great care should be taken not to mistake these two, however, as the Fiji species is extremely aggressive and will cause havoc in a tank that is planned for a Blue Damselfish. They are easy to distinguish by looks. Both have the beautiful blue body color, but the Fiji Blue Devil has a yellow band running along the lower portion of the body, which the Blue Devil does not.

  • Size of fish – inches: 3.4 inches (8.51 cm)
  • Lifespan: 15 years – Damselfish generally live up to 6 years in the wild and up to 15 years in captivity.

Fish Keeping Difficulty

The Blue Devil Damselfish are among the easiest of all marine fish to keep. They are very easy to care for, making them great for beginning saltwater hobbyists or any other marine aquarist. These beautiful “Demoiselles” adapt very easily to the aquarium without special care and will do well in either a reef environment or a fish only aquarium. They are extremely hardy and will take a variety of foods.

They tolerate a wide range of non-fluctuating temperatures, but even though they are quite durable, they can still fall ill if exposed to poor water conditions for too long. The tank needs to be 30 gallons for a single fish or a pair, so make sure water changes are frequent in such a small tank. Doing normal water changes, feeding them a variety of foods several times a day, and having proper tank mates will keep this damselfish happy and healthy.

  • Aquarium Hardiness: Very Hardy
  • Aquarist Experience Level: Beginner – They are suitable for the beginner, but tankmates must be selected with care.

Foods and Feeding

The Blue Damselfish are omnivores. In the wild they feed on filamentous algae along with tiny crustaceans, such as planktonic copepods and amphipods, and planktonic fish eggs. In the aquarium provide variety in their diet that includes both meaty and vegetable foods.

Offer meaty foods like mysis shrimp, vitamin-enriched brine shrimp, cyclops, finely shredded frozen seafoods and preparations for omnivores. Also offer flakes and other preparations for herbivores. Color enhancing foods can help maintain their bright coloring. These foods can be offered as freeze dried, frozen, pellets, flakes or fresh.

It is best to feed small amounts of food several times a day. Feeding them more often helps to dissipate any possible aggression within a tank. If feeding pellets, make sure they are wet before adding them to the tank so air will not get into their digestive tract, which can cause issues.

  • Diet Type: Omnivore
  • Flake Food: Yes
  • Tablet / Pellet: Yes – Make sure the pellets are wetted down with tank water before adding to prevent air from getting trapped in their digestive tract.
  • Live foods (fishes, shrimps, worms): Some of Diet – Only needed if you want to offer a treat or condition them to spawn.
  • Vegetable Food: Half of Diet
  • Meaty Food: Half of Diet
  • Feeding Frequency: Several feedings per day – Feed several times a day, this also helps to counter any possible aggression.

Aquarium Care

These damselfish are hardy and easy to keep in a well maintained tank. The suggested minimum tank size is 30 gallons when keeping this as a single fish or a pair, although in this small of a tank water changes need to be frequent. Regular water changes done bi-weekly will help replace the trace elements that the fish and corals use up. Guidelines for water changes with different types and sizes of aquariums are:

  • Fish only tanks:
    • Nano/Small tanks up to 40 gallons, perform 10% water changes bi-weekly or 20% monthly.
    • Medium sized up to 90 gallons, perform 15% bi-weekly.
    • Large Tanks 100 gallons and over, once water is aged and stable, can be changed 10% bi-weekly to 20% monthly, depending on bioload.
  • Reef tanks:
    • Nano/Small tanks up to 40 gallons, perform 15% water changes bi-weekly.
    • Medium sized up to 90 gallons, perform 20% to 30% monthly depending on bioload.
    • Large Tanks 100 gallons and over, once water is aged and stable, can be changed 20% to 30% every 6 weeks depending on bioload.

For more information on maintaining a saltwater aquarium see: Saltwater Aquarium Basics: Maintenance. A reef tank will require specialized filtration and lighting equipment. Learn more about reef keeping see: Mini Reef Aquarium Basics.

  • Water Changes: Bi-weekly – Do bi-weekly water changes of 15% in a reef setting or 20% monthly in a fish only tank.

Aquarium Setup

The Blue Damselfish can be happily kept in a reef setting as well as in a fish only community tank. They are moderately small in size, typically growing to 3 1/3 inches (8.5 cm) in length, and swim in the mid to lower areas of the tank. The minimum suggested tank size is 30 gallons when keeping just this fish or a mated pair. If keeping them in a group the tank should be at least 40 to 55 gallons with many hiding places in the decor. Large males are aggressive, so other tank mates should be chosen wisely.

Provide a decor of rockwork or coral that offers plenty of hiding places in nooks and crannies. Having many places to hide will reduce aggression between them and other fish in the tank. Any substrate, water movement and light is fine unless housed with corals, then these factors need to be considered for the needs of the coral. They tolerate normal water temperatures of 72˚F to 84˚F (22 – 28˚C), with pH from 8.1 to 8.4. Similar to clownfish, optimal spawning production occurs between 79°F to 83°F (26°C to 28°C).

  • Minimum Tank Size: 30 gal (114 L) – A 30 gallon tank is suggested for keeping a single fish or a male/female pair. A larger tank of 40-55 gallons or more is suggest when keeping them in a community with other fish.
  • Suitable for Nano Tank: No
  • Live Rock Requirement: Typical Plus Hiding Places – Provide places for them to hide within rockwork or coral.
  • Substrate Type: Any
  • Lighting Needs: Any – It has no special lighting requirements, though if kept with live coral the coral may need strong lighting.
  • Temperature: 72.0 to 84.0° F (22.2 to 28.9&deg C)
  • Breeding Temperature: 79.0° F – The optimal temperature for good quality eggs and larvae occurs with temperatures of 79° F to 82° F (26° – 28°C).
  • Specific gravity: 1.023-1.025 SG
  • Range ph: 8.1-8.4
  • Brackish: No
  • Water Movement: Any
  • Water Region: Bottom – They mostly inhabit the mid to lower areas of the tank. Being active swimmers they spend a good deal of time darting in and out of the crevices in the decor.

Social Behaviors

Like all damsels, the Blue Devil Damselfish can become territorial and aggressive as they get older. Juveniles and females are not overly aggressive, but large males are extremely territorial and belligerent. When kept as pairs they are also more aggressive than when alone. They can also be kept in groups as long as close attention is paid to the male/female ratio. Keeping one male with several females and/or juveniles can work in a medium or large tank as long as there are lots of hiding places. In this situation it is best to keep a close eye out for trouble.

In a community this fish is best kept with more aggressive tankmates. They will get along with moderately aggressive fish or much larger fish but will go after smaller, less aggressive fish. Fish that could be at risk include small juveniles of butterflyfish and Centropyge angelfish, as well as the more peaceful fish like gobies, blennies, cardinalfish, and firefish.

If attempting to keep them with semi-aggressive fish like dwarf angelfish, the tank should be at least 100 gallons with plenty of hiding place for the other fish. They do well with triggerfish, large angelfish, dottybacks, puffers and others that can hold their own. Do not house them with fish who can swallow them whole. It may be wise to avoid housing with any predatory fish, even if they are not big enough to eat the Blue Damselfish, as predators may keep them from coming out and eating.

Blue Damselfish can do very well in a reef setting. They make a great addition to a reef because they pose no threat to coral. They won’t bother any large or small invertebrates, though they may eat a copepod or two. Due to their aggression towards more peaceful fish tankmates should be chosen with care.

  • Venomous: No
  • Temperament: Aggressive
  • Compatible with:
    • Same species – conspecifics: Yes – May be kept as a male/female pair, or in groups of one male with several females and/or juveniles in a medium sized tank that has plenty of places to hide within the decor.
    • Peaceful fish (gobies, dartfish, assessors, fairy wrasses): Monitor – These fish will be harassed in smaller tanks, but may be okay in tanks over 100 gallons.
    • Semi-Aggressive (anthias, clownfish, dwarf angels): Monitor – Only safe in larger tanks as they may be harassed by your damsel. If housing with dwarf angelfish or the more aggressive clownfish, the tank should be 100 gallons or more with many hiding places within the rock/coral decor.
    • Safe
    • Large Semi-Aggressive (tangs, large angels, large wrasses): Safe
    • Large Aggressive, Predatory (lionfish, groupers, soapfish): Threat – Even a smaller predatory fish that cannot swallow them whole would make these damselfish too afraid to come out and feed.
    • Threat – Blue Damselfish are too aggressive for these types fish.
    • Anemones: Safe
    • Mushroom Anemones – Corallimorphs: Safe
    • LPS corals: Safe
    • SPS corals: Safe
    • Gorgonians, Sea Fans: Safe
    • Leather Corals: Safe
    • Soft Corals (xenias, tree corals): Safe
    • Star Polyps, Organ Pipe Coral: Safe
    • Zoanthids – Button Polyps, Sea Mats: Safe
    • Sponges, Tunicates: Safe
    • Shrimps, Crabs, Snails: Safe
    • Starfish: Safe
    • Feather Dusters, Bristle Worms, Flatworms: Safe
    • Clams, Scallops, Oysters: Safe
    • Copepods, Amphipods, Mini Brittle Stars: Safe – May eat some copepods but should not decimate populations.

Sex: Sexual differences

Blue Damselfish are sexually dimorphic. The females are entirely blue without any yellow or orange coloration, some females from different localities have a black ocellus on the lower posterior part of the dorsal fin. Also they have nearly translucent fins, versus totally blue fins on males. See more information by author Hiroyuki Tanaka in, “The Devils We Should Love.”

Breeding / Reproduction

All damsel species are similar to clownfish and follow the general breeding pattern of clownfish. Successful breeding requires perfect water parameters and a large, non-predatory aquarium system. Just as with clownfish, optimal spawns occur in temperatures between 79°F to 83°F (26°C to 28°C). If breeding in captivity note that brittle stars, serpent stars, wrasses and crabs will eat the eggs of damselfish. The eggs and larvae are much smaller than clownfish eggs, and the fry are difficult to rear.

The Blue Devil Damselfish will readily spawn in captivity. Each male has its own territory, which is near a nesting site. This site has rubble or half shell from a clam near the entrance. The day before spawning a female will visit the males in her colony, including any males she has spawned with in the past. When she chooses a fit and healthy male she will stop swimming, and facing upward, will flash a light ring around each eye.

Once the female has “solicited” a male whose nest she wants to inspect, the male starts a courting performance with hopes of impressing her. After she evaluates his display the female will follow the male to his nest to see how many eggs he has. She will stay up to 20 minutes inspecting his “crib” and then move on to the next male. She is not ready to lay her eggs during this “evaluation” and she is very picky. She will review a lot of potential mates, even traveling up to 325 feet (100 m) in distance from nest site to nest site.

At dawn of the next day, the female immediately spawns with the male who is largest, put on the best “dance,” and has the most eggs. If there is another female who has decided on the same male, she will wait her turn at the entrance of the nest. Up to 4 females have been seen at one nest site to spawn one at a time, one after the other, with the same male.

These nests can have almost 10,000 eggs donated from several different females. Males know that the more eggs they have in their nest, the better the chance the female will spawn with them. They have even been known to abandon their small egg clutch to take over a larger abandoned egg clutch of another male. The male will stay and protect his eggs (and the eggs of the missing male if needed) until they have hatched, which can take 4 days. The larval stage for Chrysiptera species can last between 10 to 50 days. Also see general breeding techniques under Clownfish on the Marine Fish Breeding page.

  • Ease of Breeding: Difficult – Though they will readily spawn, the eggs and larvae are quite small and the fry are difficult to rear.

Fish Diseases

Demoiselles of the Chrysiptera genus are very durable damsels once acclimated. The most dangerous time in their lives is the shipping stress they deal with. Overall they are tough and do not often fall ill, but it has been documented that there seems to be an unexplained “sudden death” that damselfish can fall victim to. There are no signs, the fish is just dead one day. They can contract any normal disease that other saltwater fish are susceptible to. But it is pretty rare unless they are captured with an illness already in motion, so a quarantine period is a good idea.

Damselfish are susceptible to Marine Ich Cryptocaryon irritans, also called White Spot Disease or Crypt, Marine Velvet or Velvet Disease Oodinium ocellatum (Syns: Amyloodinium ocellatum, Branchiophilus maris), and Uronema disease Uronema marinum. All of these are parasites.

The most easily cured of these is Crypt (salt water Ich), but they are all treatable if caught in a timely manner. Marine Velvet is a parasitic skin flagellate and one of the most common maladies experienced in the marine aquarium. It is a fast moving that primarily it infects the gills. Uronema disease, which is typically a secondary infection, is very deadly and will attack your damsel quickly and lethally.The first symptom is lack of appetite. It is most often contracted when the aquarist lowers the salinity to treat another type of illness, but doesn’t lower it far enough. This parasite thrives in mid-level brackish water salinity, which is a specific gravity of around 1.013 to 1.020.

Treat your new damselfish as gingerly as you would any other saltwater fish, and they will respond well. Anything you add to your tank that has not been properly cleaned or quarantined, including live rock, corals and fish can introduce disease. The best prevention is to properly clean or quarantine anything you want to add to the tank. For information about saltwater fish diseases and illnesses, see Aquarium Fish Diseases and Treatments.


The Blue Devil Damselfish are readily available from pet stores and online, and are inexpensive.