The Four-stripe Damselfish is handsome and hardy, but gets an attitude as it ages!

The Four Stripe Damselfish Dascyllus melanurus is a very handsome fish. It is decked out with black and white stripes across its body, another on the tail fin, and accented with a white nose and lips. This is one of the few damsels that keeps it dramatic design throughout its life, though the pattern may fade a tad with age.

This damselfish is almost identical in to its close cousin, the Three Stripe DamselDascyllus aruanus. They are bothrather small onlyreaching about 3 inches (8 cm) in length. They are also very durable and have the same behaviors and attitude. In fact, they are similar in just about every way except for the color of the tail fin, which is black only on the Four Stripe. Several other common names that emphasise this damsel’s tail coloring include Blacktail Damselfish, Blacktail Dascyllus, Blacktail Humbug, and Black-tailed Footballer.

These are spectacular looking fish that are favored by aquarists. In the ocean they will often live in a commensal relationship with corals. A school in the aquarium provides a dramatic display as they hover over a coral or the rockwork. Their durability and low cost makes them suitable for beginners, and having multiple places for juveniles to hide will help them adjust. The problem is that even though a group makes an awesome spectacle, as they grow older their attitudes will become more aggressive.

They are easy to keep, but in a captive environment their peaceful schooling behavior changes to one of pugnacious dominance. Their aggressive behavior as adults makes them only suitable for a tank with more belligerent tankmates. Companions need to be chosen carefully. These damselfish may even be aggressive towards any new additions to the tank once they are established. They have been known to attack and stress out much larger fish that will not fight back, to the point of these larger fish getting sick and/or dying from stress.

Provide a tank that is at least 30 gallons for one specimen, with rocks and/or coral that create places for them to hide. An aquarium that is 40 to 55 gallons will be needed to keep 2 to 3, and 75 gallons or more to keep a larger school. Tank mates need to be aggressive and larger semi-aggressive fish, since peaceful and smaller semi-aggressive fish will be attacked. Do not house with fish that can swallow them whole and you may also want to pass on keeping them with predatory fish.

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

Four-Striped Damsel in captivity, Dascyllus melanurus

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Juvenile Four-Striped Damsels

This little beginner fish only grows to 3″ and is found in schools in the wild. As juveniles, they are as sweet tempered as they are cute, however as they get older, in a captive environment they can wreak havoc in a community tank. They will attack less aggressive fish that are even larger than they are! A male and female may be kept, much like clownfish, however do not house them with the smaller calmer clownfish. Housing with Clarkies or other aggressive clownfish in a tank that is at least 100 gallons is possible. If you are only keeping a pair and no other fish, a 29 gallon tank is fine. Other fish will more than likely be attacked in such a small tank.

  • Kingdom: Animalia
  • Phylum: Chordata
  • Class: Actinopterygii
  • Order: Perciformes
  • Family: Pomacentridae
  • Genus: Dascyllus
  • Species: melanurus
Four-striped Damsel – Quick Aquarium Care
  • Aquarist Experience Level: Beginner
  • Aquarium Hardiness: Very Hardy
  • Minimum Tank Size: 30 gal (114 L)
  • Size of fish – inches: 3.2 inches (8.00 cm)
  • Temperament: Aggressive
  • Temperature: 72.0 to 82.0° F (22.2 to 27.8&deg C)
  • Range ph: 8.1-8.4
  • Diet Type: Omnivore
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Habitat: Distribution / Background

The Four Stripe Damselfish Dascyllus melanurus was described by Bleeker in 1854. They are found in the Western Pacific from Sumatra to Vanuatu then northward to the Ryukyu Islands. From there they are found southward to New Caledonia and Tonga. This species is not listed on the IUCN Red List of Threatened Species.

They have several additional common names relating to their black tail fin. These include Blacktail Damselfish, Blacktail Dascyllus, Blacktail Humbug, Black-tailed Footballer, Blacktailed Dascyllus, Black Tail Humbug, Black-Tail Dascyllus, Black-Tail Humbug, and of course, Fourstripe Damselfish.

About the Dascyllus Genus:

This species is a member of the very large Pomacentridae family of Damselfish and Anemonefish. It belongs to the subfamily Chrominae in the Dascyllus genus. There are currently 10 recognized species in this genus and they are only found in the Indo-Pacific.

The Dascyllus species are very deep bodied damselfish. They have a commensal relationship with corals and are often found hovering around isolated coral heads in groups. These groups range in size depending on the size of the coral. Once a Dascyllus has located a home at a coral colony it remains there.

They hide within the coral colony when frightened and use it as protection at night. In turn, the coral colony benefits from the fish waste and water movement they produce between their branches. In fact, studies have shown those corals with groups of Dascyllus grow faster and larger than those without. These damsels have the ability to visually tell the difference between a nearby herbivore and a predator, by the placement of the eyes and the shape of the mouth.

The largest dominant fish in a group is always a male, but when the dominant male is removed the largest female then transforms into the dominant male. With some species there may be several females in the process of becoming male even while subordinate. Many Dascyllus, including this species, are known to be hermaphrodites, starting life as female and turning male on demand. Yet it is also thought that there are some species that are gonochorists, where they are born as either male or female.

Similar to clownfish, this genus produces sounds to communicate. They make at least three distinct pulse sounds, and the larger the specimen the lower the frequency. Chirps and pops are audible with some species when the males are engaged in fighting, during courting, and when caring for and defending eggs in the nest site.

Of all the damselfish species only two (possibly three) from the Dascyllus genus are known to associate with anemones. These are the Domino Damsel Dascyllus trimaculatus, the Hawaiian Dascyllus Dascyllus albisella, and possibly the Strasburg’s Dascyllus Dascyllus strasburgi. Unlike their Clownfish relatives they are only found with anemones as juveniles, so are considered “facultative symbionts.” Clownfish, on the other hand, live with anemones their entire lives so are known as “obligate symbionts.”

Dascyllus are very attractive as juveniles, exhibiting dynamic color patterns. As juveniles they can be kept in a group, but as they age they become extremely territorial and mean in the confined space of the aquarium. They will be aggressive with their own kind and other damsels, as well as other fish that are not equally boisterous and pugnacious.

About Four Stripe Damselfish:

The Four Stripe Damselfish inhabit sheltered lagoons, inlets and harbors, as well as slightly open substrates. They are found at depths down to 33 feet (10 meters), and associate with isolated coral heads in their sheltered inshore habitats. They form groups of up to 25 fish hovering around coral heads.

In the wild, as juveniles settle out, they head toward coral heads and are found in groups of one dominant male and subordinate smaller females. If the male leaves or dies, the largest female transforms to a male and assumes the lead. Depending on how numerous the coral heads are, whether they arenumerous and close or spaced far apart, the reproduction will be different. With lower numbers of coral heads that are widely spaced apart, the females will stay with their male in each large coral home. When there are multiple and abundant coral heads, as in a denser reef structure, groups of females travel from one male in his small coral head to the next, mating, laying eggs and leaving the egg guarding up to the male.

These fish will not venture more than a few feet away from their corals and will quickly hide within the coral colony when frightened and use it as protection at night. The coral colony benefits from the fish waste and water movement they produce between their branches. They have the ability to tell a harmless fish from a predatory fish. This allows them more time to feed rather than hiding from everything that swims by. Similar to clownfish, this genus produces sounds to communicate.

Although they are omnivores, they lean more toward the meaty side. They feed on larval shrimp, larval crabs, algae, ostracods (small crustaceans called a Seed or Mussel Shrimp), pelagic tunicates, copepods, fish eggs and amphipods. The larger males tend to feed more on larger zooplankton.

  • Scientific Name: Dascyllus melanurus
  • Social Grouping: Groups – Adults are generally found in groups up to 25 individuals.
  • IUCN Red List: NE – Not Evaluated or not listed


The Four Stripe Damselfish is a deep bodied fish and their tail is slightly forked. They are not built for speed as well as other damselfish, so they tend to stay closer to their host coral. Some interactions, such as being engaged in fighting or when courting or caring for their nest, may result in these fish producing distinct pulsing sounds.

They typically reach just over 3 inches (8 cm) in length, though East Indies specimens are a little larger, reaching 3 1/3 inches (8.5 cm). Males are larger than females. In the wild their life span is about 6 years, though they may live up to 15 years in captivity.

Their body has 3 black vertical bands with white in between, and a white nose and lips. The base of the tail is white followed by another black band on the back half of the tailfin. The pectoral fins are clear and the pelvic fins are black. The coloration is the same for both juveniles and adults, though some adults may become a little duskier in the white areas.

Another Dascyllus speciesthat is similar in appearance to the Four Stripe Damselfish is the the Three Stripe DamselDascyllus aruanus. The Three Stripe has 3 vertical bands on the body just like the Four Stripe, but is lacking the extra black band on the end of the tail fin.

  • Size of fish – inches: 3.2 inches (8.00 cm) – They typically grow to just over 3 inches (8 cm) in length, but specimens found in the East Indies are known to reach up to 3 1/3 inches (8.5 cm).
  • Lifespan: 15 years – These damselfish generally live up to 6 years in the wild and could live up to 15 in captivity.

Fish Keeping Difficulty

The Four Stripe Damselfish are very easy to care for and are generally among the easiest marine fish to keep. They are very hardy and relatively small, making them suitable for beginning saltwater hobbyists. They are gregarious as juveniles and can be kept in a group, but they become very aggressive as they age. Take care when you put your hands in the aquarium, as an adult may bite. Though purchased with wide-eyed enthusiasm, damsels are one of the most frequently returned fish due to their eventual aggressive behavior.

These damselfish need places to hide in rockwork, which will help them adapt as juveniles. They need to be offered 2 or more small feedings a day. Although theyare quite durable, they still can fall ill if exposed to poor water conditions for too long. Doing normal water changes, feeding them a variety of foods several times a day, and having proper tank mates are important when keeping this damselfish.

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

Foods and Feeding

Four Stripe Damselfish are omnivores, but they lean more toward the meaty side. In the wild they feed on larval shrimp and crabs, fish eggs, pelagic tunicates, various small planktonic crustaceans, and to a lesser degree, algae. In the aquarium provide variety in their diet that includes mysis, enriched brine shrimp, krill, finely chopped shrimp, fish flesh and other meaty foods, as well as flakes and preparations for omnivores.

They need to be fed at least twice a day. 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 wet before adding to prevent air from getting trapped in their digestive tract.
  • Live foods (fishes, shrimps, worms): Some of Diet – Not really necessary unless trying to condition a pair to spawn.
  • Vegetable Food: Some of Diet
  • Meaty Food: Most of Diet
  • Feeding Frequency: Several feedings per day – Feed at least 2 times a day.

Aquarium Care

These damselfish are hardy and easy to keep with a well maintained tank. Regular water changes done bi-weekly will also 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 5% water changes bi-weekly.
    • 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 Four Stripe Damselfish can be kept in either a saltwater aquarium or a mini reef. They grow to about 3 inches and are very deep bodied and round, so they need plenty of room to get around. They become aggressive as they get older, so other tank mates should be chosen wisely.

They will also swim in the upper levels of the aquarium in schools as juveniles. Adults may inhabit any level if they do not have a branching coral to hover above and retreat in for shelter. To house a single specimen, provide a tank that is at least 30 gallons. A tank that is 55 gallons or more works best to keep a male and female pair or if keeping it with other aggressive larger fish. If you want to keep it other damsels, having one damsel per 50 gallons is advised.

Provide rockwork with plenty of hiding places, or even a branching small polyped stony (SPS) coral such as the Acropora sp., which will benefit from their presence. Having many places to hide will reduce aggression between them and other fish in the tank. Any substrate, water movement, and lighting is fine unless housed with corals, then these factors need to be considered for the needs of the coral. Normal water temperatures between 72ËšF to 82ËšF (22 – 28ËšC) and a pH from 8.1 to 8.4 will keep this damselfish healthy. 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 one specimen, 55 gallons or more for a pair.
  • Suitable for Nano Tank: Sometimes – A Nano will work if the Four-stripe Damsel is the only fish in the tank.
  • Live Rock Requirement: Typical Amount – Provide a few 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 82.0° F (22.2 to 27.8&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: Middle – Juveniles tend to stay near the top, but adults will stay close to a host coral if present, hovering above it for safety. If coral is not present they may inhabit all areas of tank.

Social Behaviors

Like all damsels, the Four Stripe Damselfish can be territorial and aggressive, especially as they get older. They are fine as juveniles, either in a school or alone, but as they mature their attitude grows bolder and more belligerent. It is best to keep just one per tank, unless it is a male/female pair, or the tank is large with plenty of hiding places. Once paired they are even more aggressive than when alone.

Tank mates need to be other fish as aggressive as they are, or much larger. Smaller semi-aggressive fish and peaceful fish will be attacked as this fish ages. These damsels can be kept together with other larger fish in good sized tanks, but watch them closely to be sure their aggression doesn’t become destructive. If attempting to keep with smaller semi-aggressive fish, like dwarf angelfish, the tank should be at least 100 gallons with plenty of hiding places for the other fish.

Ideally try to house them with triggerfish,the more aggressive large angelfish, larger 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 Four Stripe Damselfish. This is because of these damsels’ ability to recognize a predator, which may keep them from coming out and eating.

They will work great in a reef and really pose no threat to corals. Their presence can actually benefit branching small polyped stony (SPS) corals. Invertebrates are generally safe though small crustaceans like copepods, amphipods, and others may be eaten. Only if the tank is very large with a huge colony of established copepods, will they not be depleted. Be cautious with small ornamental shrimps, like the Sexy Anemone Shrimp Thor amboinensis, as they may be attacked.

  • Venomous: No
  • Temperament: Aggressive
  • Compatible with:
    • Same species – conspecifics: Sometimes – A male/female pair will need 55 gallons or more, with plenty of places for retreat in the rockwork. Otherwise keep only one damsel per 50 gallons.
    • Peaceful fish (gobies, dartfish, assessors, fairy wrasses): Threat – These damsels are too aggressive for peaceful fish.
    • Semi-Aggressive (anthias, clownfish, dwarf angels): Monitor – Four Stripe Damselfish are usually too aggressive for fish in this group. If attempting to house with aggressive dwarf angelfish, it should be in a tank that is at least 100 gallons or more.

    • Monitor – Although larger dottybacks should be okay, Six-line or Eight-line wrasses may be picked on, depending on the individual damsel and the tank size.
    • Large Semi-Aggressive (tangs, large angels, large wrasses): Monitor – Only larger more aggressive versions of these fish are safe, more peaceful types may fall victim to harassment.
    • 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 – The Four Stripe Damselfish are too aggressive for these slower types of fish.
    • Anemones: Safe
    • Mushroom Anemones – Corallimorphs: Safe
    • LPS corals: Safe
    • SPS corals: Safe – These damsels are beneficial to branching small polyped stony (SPS) corals such as Acropora sp.
    • 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: Monitor – Be cautious with small ornamental shrimp, like sexy shrimp, as they may become dinner.
    • Starfish: Safe
    • Feather Dusters, Bristle Worms, Flatworms: Safe
    • Clams, Scallops, Oysters: Safe
    • Copepods, Amphipods, Mini Brittle Stars: Safe – Copepod and amphipod populations should be well established in a larger tank, or they can easily be diminished by the Four Stripe Damselfish.

Sex: Sexual differences

Males are larger and are the dominant fish in the group or pair. They are thought to be hermaphrodites, starting life as female and turning male on demand. Some dominant females may have slightly undeveloped male organs to allow them to quickly turn into a male if the dominant male disappears.

Breeding / Reproduction

The Four Stripe Damselfish have been bred in captivity, following the general pattern of clownfish. The male is the larger and dominant fish, with the females changing to male as they move up the hierarchy. 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, and are difficult to rear.

Four-stripe Damsels have similar spawning habitsas the Three Stripe Damsel. Spawning in the Three Stripe Damsel was observed for 2 to 4 days around the new and full moon in the reefs around Sesoko Island, Okinawa. Spawning was done early in the morning during the months of June to September. They may spawn more often in warmer waters. There is a pecking order in which the alpha female spawns with the alpha male first, then other females will spawn in descending order. Males may even try to spawn with females in a group nearby if that other male is small.

Successful breeding requires perfect water parameters and a large, non-predatory aquarium system. Similar to clownfish, optimal spawns are between 79°F to 83°F (26°C to 28°C). In typical Dascyllus genus fashion, the male chooses a spawning site which can be a rock, dead coral branch, coral rubble, or flat rock.

To attract a female, the male will engage in signal jumping and will produce sounds. Signal jumping is the behavior of dipping up and down quickly. Once the female sees that the male is ready to spawn, she will join him. Then both turn almost completely white, vibrate, and then simultaneously deposit their gametes on the nesting site.

After the eggs are laid and fertilized, the male produces more pulse sounds as he defends the nest. One clutch can have over 1,000 eggs. The male will oxygenate the eggs and remove any that are undeveloped. He will viciously guard his nest until they hatch. The eggs will hatch in 2 to 2.5 days, right after sunset. The larval stage is 22 to 24 days in aquaria. Due to similarities, see breeding techniques under Clownfish on the Marine Fish Breeding page.

  • Ease of Breeding: Difficult – The eggs and larvae of damselfish are quite small and the fry are difficult to rear.

Fish Diseases

Dascyllus are very durable damsels, even when juveniles. However there does seem to be an unexplained “sudden death†that damselfish can occasionally 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 infects the gills. Uronema disease, which is typically a secondary infection, is very deadly and will attack your fishquickly 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 expensive 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 Four Stripe Damselfish are inexpensive and readily available from pet stores and online.