The Regal Damselfish (Neopomacentrus cyanomos) known to tropical fish keeping enthusiasts as the Regal Demoiselle, Cresecent Damselfish, Violet Damselfish, Yellow-tailed Damselfish, and Regal Damsel is found in the Indo-West Pacific and ranges from Red Sea and East Africa to the Philippines, north to southern Japan, south to northern Australia and Melanesia.
The Regal Demoiselle is only found in a few areas of their range, so they are definitely not common, however, when they are found there tend to be abundant numbers of them. In Tanzanian waters, they are found in only a few locations, but in these spots their shoals are huge.
Although not native to the Atlantic, Regal Damselfish like Lionfish are regarded as an invasive species.
In 2013, Regal Damselfish were sighted on nearshore coral reefs in the southwestern Gulf of Mexico near Coatzacoalcos, Mexico and in 2014 and 2015, individuals were observed on reefs near Veracruz City, and at Madagascar Reef off the northwestern coast of the Yucatán Peninsula. More recently in 2017, Regal Damselfish were found in the northern Gulf of Mexico offshore of Alabama, Florida, Louisiana, and Mississippi. In 2022, they were spotted off of West Palm Beach and in the Keys, and in July of 2019, they were recorded from various locations on the western side of Trinidad, where they were believed to hitch hike on oil platforms that were transported from the Indo-Pacific. In February 2021, several individuals were observed at multiple locations in the reefs off the southern coast of Aruba.
Adult Neopomacentrus cyanomos inhabit inshore and offshore coral reefs, harbors, protected outer reef slopes, and other current prone habitats where they can be found close to shelter feeding on zooplankton and off the substrate. Although usually found in loose shoals close to shelter at depths from 9 to 100 feet. Adult Regal Damselfish are often found in harbors in large, loosely formed shoals in depths from near surface to about 82 feet. Juveniles are found in these same areas in tight shoals around the same depths.
The Regal Demoiselle is a deceptively colored fish. When a shoal is seen on the reef, they appear to be a blackish grey color but under light, they are actually very colorful, especially in an aquarium environment.
The overall body color of the Regal Damselfish is a gunmetal gray color. The upper body and head has a greenish tint. The lower body has a grayish tint and the scales on the body have a blue mark on them. There is a black or yellow spot just behind the gill plate and a black spot on the base of the pectoral fins. The rear base of the dorsal fin is distinguished by a yellow or white spot, and the dorsal, anal, and lyre shaped caudal fins are lined a bright or pale yellow. The spines on the pectoral fins are yellow, and light blue on the pelvic fins.
Similar to the Brown Chromis native to Atlantic waters, the native fish have dark margins on the tail and a dark spot at the base of the pectoral fin.
The Regal Damselfish is a hardy, relatively peaceful species that is easy to keep in an aquarium environment. They are best housed in groups of at least 6 to 9 or more individuals in a mature reef or FOWLR tank of at least 55 gallon capacity, with a sand or fine gravel substrate and plenty of live rock arranged into hiding places and plenty of free swimming space. Like most damsels, juvenile Regal Damselfish tend to become territorial as they become adults and may beat up more peaceful species. They are best housed in a FOWLR tank with semi-aggressive species.
Regal Damselfish have been successfully bred in an aquarium.
Before spawning, the males change the colors on their dorsal to attract a mate. Prior to mating pairing occurs and the male cleans a patch of rubble or shell on the hard substrate for the eggs to be laid. After a brief “dance” the female deposits her adhesive demersal eggs on the substrate. After the male fertilizes the small elliptical eggs attached by adhesive filaments to the substrate, he guards and aerates the clutch until they hatch out in about 4 to 5 days. The tiny fry in their larval stage will drift with the current as plankton feeding on zooplankton and phytoplankton for 17 to 20 days before settling to the bottom as partially developed damselfish. Males will often mate with multiple females during the spawning season.
Regal Damselfish feed on zooplankton and small crustaceans off the substrate in their natural habitat. In an aquarium environment they will accept high quality omnivore flakes and pellets but should also be given fresh, frozen, or freeze dried algae, Mysis shrimp, brine shrimp, krill, plankton, chopped shrimp, scallops, clam, etc. Feeding small portions 2 to 3 times a day is recommended.
Regal Damselfish (Neopomacentrus cyanomos) are occasionally available to tropical fish keeping enthusiasts online from a variety of wholesale and retail sites at prices from $15.00 to $25.00 at a purchase size: 1 – 1.25″.
Minimum Tank Size: 55 gallons
Aquarium Type: Reef or FOLR
Care Level: Easy
Temperament: Semi Aggressive
Aquarium Hardiness: Hardy
Water Conditions: 72-78°F, dKH 8 to 12, pH 8.0 – 8.4, sg 1.020-1.025
Max. Size: 2.75″
Color Form: Gray, Black, Yellow
Diet: Omnivore
Compatibility: Reef
Origin: Indo-West Pacific, Gulf of Mexice, Atlantic
Family: Pomacentridae
Lifespan: 5 years
Aquarist Experience Level: Beginner