Pomacanthus paru, also known by its common name the French angelfish, is a slow growing coral reef fish from the tropics with a distinctive and striking appearance. In terms of fish taxonomy, French Angelfish fall under the fish order of Perciformes and under the family Pomacanthidae, which contains other species of marine angelfish. The closest relative of the French Angelfish is the Gray angelfish, or Pomacanthus arcuatus.

Description

The French angelfish has a compressed and streamlined body plan. This means that the fish is vertically compressed, making it appear quite thin. P. paru are also a decently large species of reef fish with males growing to an impressive size of around 18in, or 45cm, and females growing to a slightly smaller size. The head is deep with a short snout ending in a small mouth which contains numerous bristle-like teeth. There is an obvious spine at the corner of the preoperculum while there are no spines on the operculum or under the eye. The dorsal fin contains 10 spines and 29–31 soft rays while the anal fin contains 3 spines and 22–24 soft rays. This species attains a maximum total length of 41.1 cm. The colorations of the fish are quite striking with both males and females having a black or dark gray body that provides a great source of contrast with the tips of their scales being painted a bright yellow. The adults are also mainly black but most of the scales on the body have a golden-yellow edge. They have a white mouth and a yellow orbit. The pectoral fins have a wide orange-yellow band and the dorsal fin has a long yellow filamentous extension growing from its soft-rayed part. Juvenile French Angelfish look extremely different from how adults of the species appear. Although both juveniles and adults have a black or dark gray body, where they differ is in markings. Juveniles are almost completely black apart from five vertical yellow bands, that run down the entire height of their body, the first around the mouth and the last at the caudal peduncle.

Distribution

French angelfish can be found in the western Atlantic from Florida to the Gulf of Mexico and down towards Brazil and the Caribbean, including the Antilles, Roatan, and the eastern Atlantic from around Ascension Island and St. Paul's Rocks. These fish can be seen in water depths above about 15ft, or about 4.5m, and they have also been reported at depths within the mesophotic zone, which is between 30m and 150m, or about 100ft - 500ft.

Biology

French angelfish are common on rocky and coral reefs where it is normally encountered in pairs, frequently in the vicinity of sea fans. Its diet comprises sponges, algae, bryozoans, zoantharians, gorgonians, hydroids, coral and tunicates. These pairs are highly territorial, and typically both vigorously defending their territory from their neighbours. Juveniles act as cleaner fish and establish cleaning stations. Species recorded as being clients of juvenile French angelfish, include jacks, snappers, morays, grunts, surgeonfishes and wrasses.. These fish are active during the daylight hours, but seek shelter in their designated hiding spot where they return every night. They can produce a knocking sound when alarmed. Similar to many other fish species, you can tell the age of a fish by using its otoliths. Otoliths are also commonly referred to as ear stones or ear bones. They are made up of the same thing shells are made out of, which is calcium carbonate, and are only found in bony fishes. Researchers used the sagittae otolith in French Angelfish, since it creates yearly bands that are see-through, which suggest that the fish's otoliths have a linear relation to the fish's age. The same study also found that P. paru grows exponentially in relation to its standard length. With this ability to accurately determine a fish's age, scientists have found that P. paru can live for over twenty-seven years.

Reproduction

When it comes to mating, there are no obvious courtship displays or clear sexual dimorphism between the sexes. Firstly for P. paru, once a mate has been found, they will stick with each other for the rest of their lives. This means that these fish mate for life. Not much is truly known about the mating patterns of P. paru, with it rarely being observed. However, from what has been observed, the fish, in mating pairs, would swim up the water column, with one in front and one directly behind the other. This reproductive mating behavior is truly unique because it has only ever been reported to occur right around sunset, or dusk. At dusk, the pair swim upwards in a wide, shallow curve from the substrate, travelling around 7 to 10 m horizontally as they climb to a 2 or. As they ascend, both angle their bodies slightly, with their vents very close together, even touching. They hold this posture throughout the zenith of their curve separating as they descend. Neighbouring pairs were observed undertaking similar movements above the reef at roughly the same time. The observers were unable to ascertain if gametes were released in these displays. Neighbouring pairs were not seen interfering with these displays. This species is a protogynous hermaphrodite; the female can change sex to become a male if no male is present.

Feeding Behavior

With P. paru living in and around coral reefs and rocky shores, the diet of these fish is also just as interesting as their mating behavior. As adults, these fish primarily feed on sponges with around 70% of their diet consisting of sponges. Adults of this species have comb-like teeth that help to grind up pieces of sponges. Surprisingly juvenile diets do not primarily consist of sponges. In fact, juveniles of this species feed by consuming ectoparasites on larger fishes, due to this the juveniles spend a huge portion of their time at or near their cleaning stations. As P. paru juveniles grow in size they become more generalists when it comes to species of sponge they eat, eating around twelve to fifteen sponge species, which is similar to their adult diet. This shows there is a direct relationship between the size of the juvenile and how much sponges contribute to their diet, with large juveniles eating more sponges than smaller juveniles.

Juvenile Cleaning Stations

Out in the Caribbean, there are a few fish families that, similar to juvenile P. paru, provide cleaning services, and these cleaning services are not limited to fish, but young sea turtles who stop by for short and quick cleaning sessions. In these cases, juvenile P. paru primarily clean the sea turtles’ heads, carapace, and plastron. These cleaning services are important in maintaining the ecosystem because the parasite are removed from the ecosystem before they have a chance to spread to other fish.

Conservation Status

According to the IUCN red list of endangered animal species, the French angelfish is currently listed as least concern. However, it is very possible that in the coming years this fish species moves from least concern to near threatened or even vulnerable. This is in large part due to the marine pet trade, also known as the marine ornamental trade. In Brazil alone, the French angelfish is the fifth most exported in the Brazilian fish trade, not to mention that they are also caught as bycatch as well. Due the fact that French angelfish live so long, and are slow to grow, along with their popularity in the fish trade, it is not hard to see how this fish species becomes more endangered thanks to humans. Furthermore, these fish are also quite late to reach sexual maturity. Which means that these fish can not reproduce as rapidly as other fish species.

Threats to French Angelfish

Endoparasites, or parasites that live inside their host's body, are a cause for concern. In a captive specimen in Georgia, researchers found parasites on the foregut wall of the fish. The specific parasite that was found was a species of worm from the genus Enterogyrus. The way in which these parasites attach themselves to their host completely surprised scientists because the parasites attach themselves perpendicularly to the folds in the foregut.

Systematics

The French angelfish was first formally described as Chaetodon paru by the German physician and naturalist Marcus Elieser Bloch (1723–1799) with the type locality given as Brazil and Jamaica. The species is placed by some authorities in the subgenus Pomacanthus,. The specific name of this species, paru is the Portuguese name for this species.

Utilisation

The French angelfish is common in the aquarium trade, collection and export to the United States and European markets being common in Brazil. It has been bred in captivity. It is harvested for food, its flesh being considered highly palatable, although it has been reported to be a source of ciguatera poisoning in humans.