Pomacentrids, commonly known as damselfishes and anemonefishes, are one of the most abundant and widely-studied families of tropical reef fishes. Small and brightly colored, they are popular aquarium fish. The family Pomacentridae consists of approximately 28 genera and 335 species. They tend to be territorial and can be aggressive, although this is not the case for the non-territorial, free-swimming planktivores or the anemonefishes (Amphiprion and Premnas) that live commensally with anemone hosts. Damselfishes are largely herbivorous, sometimes tending “gardens” of filamentous algae, but may eat tiny invertebrates, or in the case of anemonefishes, anemones and other organisms living symbiotically with anemones. Damselfishes manifest a range of reproductive behaviors, with groups that are polygynous, promiscuous, polyandrous, and monogamous. Anemonefishes are able to change from male to female under certain conditions (see Reproduction: Mating Systems).
The damselfishes are some of the most common and conspicuous coral reef fishes in the region and are often selected as the subjects for ecological and behavioral studies. Their taxonomy is straightforward; there are only four genera in the Caribbean with relatively few species. Two genera include several species each: the ubiquitous Stegastes with six species (and one fresh-water species) and Chromis with two shallow and four deep-water species. There are two Abudefduf species and the single Microspathodon chrysurus. The Caribbean Stegastes have been moved around from genus to genus over the recent past, spending some time as Eupomacentrus and Pomacentrus.
Pomacentrid larvae closely resemble juvenile damselfish in form and are easy to recognize. Larval damselfishes are characterized by a rounded body with a wide caudal peduncle, continuous spinous and soft dorsal fins, large round eyes, a relatively small terminal mouth, and the absence of head spines. Distinguishing species for the larval and newly-settled stages can be a challenge in this family where meristics can broadly overlap, especially within Stegastes. The marking patterns that separate species of Stegastes typically diverge only at the late juvenile stage and new recruits can share many of the features that will later distinguish the species (i.e. ontogenetic homology). The two regional Abudefduf are also very similar as larvae and new recruits. As a result, some descriptions of damselfish early life history and many illustrations of small juvenile damselfishes in guidebooks and on the web are incorrect.
Pomacentrids are found throughout the world in tropical and warm temperate waters, with the majority of species occurring in the Indo-west and central Pacific region.
Biogeographic Regions: oriental (Native ); ethiopian (Native ); neotropical (Native ); australian (Native ); oceanic islands (Native ); indian ocean (Native ); atlantic ocean (Native ); pacific ocean (Native )
Other Geographic Terms: cosmopolitan
Damselfishes, which include the anemonefishes (Amphiprion and Premnas), range from five to 36 cm, with most specimens less than a foot long. Their bodies tend to be high, oval and laterally compressed, with the lateral line interrupted. The single, continuous dorsal fin has eight to 17 spines and 10 to 18 soft rays, the anal fin usually has two spines (occasionally three), and the caudal fin is typically forked. Adults of many species have filamentous extensions on all but the pectoral fins. Ctenoid scales are present on the body, head, and unpaired fin bases. Pomacentrids, with a few exceptions, have one rather than two nostrils on each side, and a small mouth. The palate is toothless, and the floor of the mouth contains a pharyngeal plate (a triangular fused tooth plate). Teeth may be arranged in one or two rows and may be incisorlike, especially in territorial forms that graze on algae, or conical, often seen in forms that live in the water column and catch small organisms (See an illustration of tooth morphology in fish). Coloration of adult damselfishes ranges from brilliant to drab and can vary with mood and time of day. Juveniles, especially in the territorial bottom-dwellers, often possess different, brighter colors than adults of the same species. (Click here to see a fish diagram).
In most pomacentrid groups males and females differ ( sexual dimorphism) externally only in the form of the urogenital papilla, and (except for one species) lack permanent sexual dichromatism. The majority, however, do assume sex-specific colors during spawning. Usually the male, but sometimes the female (and sometimes neither), assumes courtship colors, the pattern and intensity of which vary according not only to species, but also to geographic and perhaps other factors. Adult males tend to be larger than adult females, but the opposite is true for anemonefishes (Amphiprion and Premnas), which are protandrous hermaphrodites: a male can change sex if the dominant female (the largest fish in the group) dies. In these fishes a single individual possesses ovarian as well as testicular tissue.
Other Physical Features: ectothermic ; bilateral symmetry
Sexual Dimorphism: sexes alike; female larger; male larger; sexes colored or patterned differently; male more colorful
Pomacentridae primarily inhabit tropical reef habitats. Some live along steep edges of the reef, and others in sandy sheltered lagoons. In each ocean a few species occupy warm temperate waters, and three estuarine species can sometimes be found in fresh water. Some school in the water column, some live on rocky areas or sea-grass beds, and fishes of the subfamily Amphiprionina (anemonefishes) always dwell in association with sea anemones. A few deep-water species occur at the edge of the shelf at depths below 100 m, but most pomacentrids occupy shallow water between two and 15 meters deep.
Habitat Regions: temperate ; tropical ; saltwater or marine
Aquatic Biomes: benthic ; reef ; coastal ; brackish water
Bottom-dwelling damselfishes feed, for the most part, on algae and small invertebrates. They may tend “gardens” of filamentous algae, or in the case of anemonefishes, feed on the anemone itself or other organisms that are commensal with the anemone. One species of damselfish, Cheiloprion labiatus, or largelipped puller, eats the polyps of live coral. Damselfishes that live in the water column tend to feed on plankton and zooplankton.
Primary Diet: carnivore (Eats non-insect arthropods); herbivore ; omnivore ; planktivore
Damselfishes are numerous and common on tropical reefs, and as such are an established element of those habitats. Many of them affect the growth of algae on the reef, encouraging algal growth in some areas while using the algae as a food source. The anemonefishes provide some protection and bring in sources of nourishment for their anemone hosts, and some groups of juvenile damselfishes clean other fishes.
Species Used as Host:
- sea anemones
Reef damselfishes gain protection from predators by hiding in coral shelters, anemonefishes by living in close contact with a host anemone, and the free-swimming damselfishes by schooling. Each group’s method of protecting itself applies to its eggs as well, except for midwater damselfishes, which must establish temporary shelter for spawning and egg laying.
Known prey organisms
This list may not be complete but is based on published studies.
Life History and Behavior
Damselfishes (Pomacentridae) use a variety of visual, olfactory, tactile, and auditory cues to communicate in different situations. During courtship damselfishes respond to the sight of spawning colors and ritualized movements performed by a potential mate (see Reproduction: Mating Systems). Such movements may also signal the location of territory to other males or encourage reproductive synchrony. Anemonefishes (Amphiprion and Premnas) appear to use perception of individual color differences to recognize their monogamous partner. In addition to visual cues, male damselfishes use sound to ward off other males and sometimes as part of courtship and spawning rituals. They may touch and nip females to guide them toward a nest. Chemical cues from some damselfishes may encourage conspecific (individuals of the same species) juveniles to establish nearby territories and may discourage other groups of damselfish from settling. Young anemonefishes use visual and chemical cues when choosing a preferred species of anemone as host.
Communication Channels: visual ; tactile ; acoustic ; chemical
Perception Channels: visual ; tactile ; acoustic ; chemical
Pomacentrid larvae hatch from a clutch of 50 to 2500 eggs, depending on the species. For some the planktonic stage may last only a day while others drift in the open ocean for a few weeks. Juveniles settle in reef areas and their coloration can be quite different from that of adults of the same species. In anemonefishes (Amphiprion and Premnas) one sexually active pair is dominant over a group of juveniles. The young grow slowly in this situation and do not reach sexual maturity until they can replace one of the dominant fish.
Little is known about the lifespan of damselfish, but Eupomacentris spp. live an estimated six to eight years. Some species may live 10 to 12 years in the wild and perhaps 18 years in captivity.
The majority of damselfishes engage in a range of ritualized behavior to attract mates and prepare nest sites. The male, and sometimes the female, begin to groom and tend a rocky surface several days before spawning. He removes invertebrates and algae with his mouth, sometimes allowing certain elements to remain, as is the case with Hypsypops rubicundus, a species that weeds out all but red algae from the site. Courtship activities accompany cultivation of the potential nest. Males may give auditory signals; depending on the stage of courtship, species of Eupomacentrus emit three different types of chirps and grunts. They may also display visual signals, with most damselfish males assuming distinct colors for courtship, and many executing various movements to entice the female to the nest site. Such movements have been described as “leading,” which may include quick bursts of swimming and intermittent hovering in front of the female, “signal-jumping,” or rapid up and down movements, and “dipping,” which is similar to signal-jumping and includes an abrupt descent.
One group of damselfishes, the anemonefishes (subfamily Amphiprioninae), enter into permanent monogamous pairings and as a rule display a simplified pattern of courtship. Fish in this subfamily are protandrous, a mating system in which male individuals can become female. Ambosexual (neither sperm- nor egg-producing tissues are active) juveniles live on an anemone with a sexually mature male and female pair. If the female dies, her male partner develops into a female to take her place. The largest juvenile grows rapidly and replaces him as the dominant male.
Mating System: monogamous ; polyandrous ; polygynous ; polygynandrous (promiscuous)
Damselfishes appear to spawn year-round, with many groups increasing spawning activity in early summer. In the subtropics spawning is usually limited to the warmer months of the year, but a few spawn in fall or winter. It is common for reef-dwelling damselfishes to spawn in accordance with lunar rhythms, with greatest activity occurring near the full and new moons. Spawning usually takes place in the morning. Synchronous spawning has been observed, and in some species, the higher the number of individuals in a group, the higher the degree of synchrony. Some damselfishes spawn within their permanent territory, while others (planktivorous damselfishes that live in the water column) must seek temporary territories for courtship and spawning. Location of a spawning site may involve solitary males or may be a communal activity in which schools of males, juveniles, and females travel until the males form a colony of territories on an acceptable site. Site choice varies according to species and may include rock ledges, cleaned coral branches, algal turf, empty shells, or the roofs of caves. Males typically prepare the site for spawning and then attract gravid (egg-bearing) females to the nest (see Reproduction: Mating Systems). The male guards the nest from predators and other males while the female lays her eggs in long rows, forming a solid, uniform mass of eggs in a single layer. The eggs are demersal (adhere to the substrate), and clutch size varies from 200 to 2500 eggs depending on the species.
Polygyny is common: one male may guard the eggs of several females, and damselfish harems have also been observed. Some damselfish are promiscuous, and still others are monogamous. Polyandry has been reported only in an anemonefish, although monogamy is the general rule for anemonefishes (Amphiprion and Premnas). These fish stay paired for at least a year and sometimes for their entire lifetime. They spawn year-round, usually near the full moon. Hypotheses suggest that lunar spawning occurs because of the increased light for nest tending, the greater currents for larvae dispersal, and the relative abundance of spawning invertebrates as a food source. Anemonefish most frequently live in single pairs, along with a group of sexually immature individuals, in association with an anemone (see Reproduction: Mating Systems). Groups containing several males and females may occasionally occur if the fish population density is extremely high. Spawning occurs at the base of the anemone, on a rock surface, or, if the anemone lives on sand, on a surface the fish drag near the anemone. The male clears the nest site by biting at the tentacles of the anemone until they withdraw, and then leads the female there for spawning, during which both fish quiver and bite the nest surface.
Key Reproductive Features: iteroparous ; seasonal breeding ; year-round breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sequential hermaphrodite (Protandrous ); sexual ; fertilization (External ); oviparous
Male damselfishes (and in very few cases, females) guard their eggs until they hatch. They remove detritus, sand, and fungus-afflicted eggs, fan the eggs, and guard against predators. Most become more aggressive when egg-tending, but this is not the case with anemonefishes (Amphiprion and Premnas). In general fry are left to care for themselves after hatching, but in one Indo-Pacific species, Acanthochromis polyacanthus, parents guard their school of young near the spawning cave for three to six weeks.
Parental Investment: male parental care ; female parental care
Molecular Biology and Genetics
Statistics of barcoding coverage
Specimens with Sequences:4125
Specimens with Barcodes:3601
Species With Barcodes:259
Three pomacentrid species, Chromis sanctaehelenae, Stegastes sanctaehelenae, and Stegastes sanctipauli, are listed as vulnerable.
Relevance to Humans and Ecosystems
No specific information was found concerning any negative impacts to humans.
Many damselfishes are brilliantly colored and are popular aquarium fish. In aquarium settings they can be aggressive, but are extremely hardy. In some areas bordering the Indian Ocean people eat damselfishes that they catch in traps or with hooks, but in general pomacentrids are not used for food.
Positive Impacts: pet trade ; food
Pomacentridae is a family of perciform fish, comprising the damselfishes and clownfishes. They are primarily marine, while a few species inhabit freshwater and brackish environments (e.g., Neopomacentrus aquadulcis, N. taeniurus, Pomacentrus taeniometopon, Stegastes otophorus). They are noted for their hardy constitutions and territoriality. Many are brightly colored, so they are popular in aquaria.
Around 360 species are classified in this family, in about 29 genera. Of these, members of two genera, Amphiprion and Premnas (subfamily Amphiprioninae), are commonly called clownfish or anemonefish, while members of other genera (e.g., Pomacentrus) are commonly called damselfish. The members of this family are classified in four subfamilies: Amphiprioninae, Chrominae, Lepidozyginae, and Pomacentrinae.
The name of the family is derived from the Greek words; poma roughly translates to the English "cover", referring to the fishes' opercula, and kentron is Greek for sting. The name refers to the serrations found along the margins of the opercular bones in many members of this family.
Distribution and habitat
Pomacentrids are found primarily in tropical seas, with a few species occurring in temperate waters (e.g., Hypsypops rubicundus). Most species are found on or near coral reefs in the Indo-West Pacific (from East Africa to Polynesia). The area from the Philippines to Australia hosts the greatest concentration of species. The remaining species are found in the Atlantic or eastern Pacific. Some species are native to freshwater or brackish estuarine environments.
Most members of the family live in shallow water, from 2 to 15 m (6 ft 7 in to 49 ft 3 in) in depth, although some species (e.g., Chromis abyssus) are found below 100 m (330 ft). Most species are specialists, living in specific parts of the reef, such as sandy lagoons, steep reef slopes, or areas exposed to strong wave action. In general, the coral is used as shelter, and many species can only survive in its presence.
The bottom-dwelling species are territorial, occupying and defending a portion of the reef, often centered around shelter. By keeping away other species of fish, some pomacentrids encourage the growth of thick mats of algae within their territories, leading to the common name farmerfish.
Pomacentrids have an orbiculated to elongated body shape, which is often laterally compressed. They have interrupted or incomplete lateral lines and they usually have a single nostril on each side (some species of Chromis and Dascyllus have two on each side). They have small- to medium-sized ctenoid scales. They have one or two rows of teeth, which may be conical or spatulated.
They display a wide range of colors, predominantly bright shades of yellow, red, orange, and blue, although some are a relatively drab brown, black, or grey. The young are often a different, brighter color than adults.
Pomacentrids are omnivorous or herbivorous, feeding on algae, plankton, and small bottom-dwelling crustaceans, depending on their precise habitats. Only a small number of genera, such as Cheiloprion, eat the coral where they live.
Before breeding, the males clear an area of algae and invertebrates to create a nest. They engage in ritualised courtship displays, which may consist of rapid bursts of motion, chasing or nipping females, stationary hovering, or wide extension of their fins. After being attracted to the site, the female lays a string of sticky eggs that attach to the substrate. The male swims behind the female as she lays the eggs, and fertilises them externally. Varying by species, brood sizes range from 50 to 1000 eggs.
The male guards the nest for the two to seven days that it takes for the eggs to hatch. The transparent larvae are 2 to 4 mm (0.079 to 0.157 in) long. They go through a pelagic stage which, depending on the species, can last as little as a week or more than a month. When they arrive at a suitable environment, the young settle and adopt their juvenile colors.
In captivity, pomacentrids live up to 18 years, but they probably do not live longer than 10 to 12 years in the wild.
About 28 genera in four subfamilies are recognized:
- Jenkins, A.P. & G.R. Allen (2002). "Neopomacentrus aquadulcis, a new species of damselfish (Pomacentridae) from eastern Papua New Guinea". Records of the Western Australian Museum 20: 379–382.
- Froese, Rainer, and Daniel Pauly, eds. (2007). "Pomacentridae" in FishBase. July 2007 version.
- Allen, G.R. (1975). Damselfishes of the South Seas. Neptune City, NJ: T.F.H. Publications. ISBN 978-0-87666-034-8.
- Nelson, J.S. (2006). Fishes of the World. Hoboken: John Wiley and Sons. ISBN 978-0-471-25031-9.
- Allen, Gerald R. (1998). Paxton, J.R. & Eschmeyer, W.N., ed. Encyclopedia of Fishes. San Diego: Academic Press. pp. 205–208. ISBN 0-12-547665-5.
- Pyle, R.L., J.L. Earle & B.D. Greene (2008). "Five new species of the damselfish genus Chromis (Perciformes: Labroidei: Pomacentridae) from deep coral reefs in the tropical western Pacific". Zootaxa 1671: 3–31.
- Ivan Sazima, Cristina Sazima, Ronaldo B. Francini-Filho, Rodrigo L. Moura (September 2000). "Daily cleaning activity and diversity of clients of the barber goby, Elacatinus figaro, on rocky reefs in southeastern Brazil". Environmental Biology of Fishes 59 (1): 69–77. doi:10.1023/a:1007655819374. 10.1023/A:1007655819374.
- Thresher, R.E.; Colin, P.L.; Bell, L.J. (1989). "Planktonic duration, distribution and population structure of western and central Pacific damselfishes (Pomacentridae)". Copeia 1989 (2): 420–434. JSTOR 1445439.
- Nelson, J. S. (2006). Fishes of the World (4 ed.). Hoboken, NJ: John Wiley & Sons. ISBN 978-0-471-25031-9.
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