Blue-striped AngelfishBlue-lined Angelfish

Habitat: Natural geographic location:      Described by Temminck and Schlegel in 1844, the Blue-striped Angelfish or Blue-lined Angelfish is found in southern Japan, southern Korea, Taiwan, Hong Kong, and Vietnam. This species is commonly seen on rocky shores at depths between 16 to 197 feet (5 - 60 meters) in southern Japan from the Izu Islands southward, but is scarce in the Ogasawara Islands (Bonins) and also is very curiously absent from the Ryukyu Islands (around Okinawa).
     It is very mysterious that the Blue-striped Angelfish is completely absent from the sea around Okinawa. No diver or collector has observed or collected any specimen at all, but many records of collection of this angelfish were made from Taiwan. It is also abundant at the large Kyushu Island of Japan.
     The Blue-striped Angelfish lives in its natural habitat singly or in a small group. They are often observed by divers around southern Japanese waters at the depth of 10 meters or so, but when it is a juvenile will be in waters less than 5 meters . One of my friends, a collector, encounters and catches juveniles with a hand net on rare occasions in southern Miyazaki, Kyushu.
     A distinct variation is known from Vietnam that has a more complicated color pattern especially on the head and face, similar in appearance to the Orangeface Angelfish C. chrysocephalus from Indonesia. All of the large adults from Vietnam have such a color pattern though the pattern varies between individuals.
     This species is closely related to the very similar Maze Angelfish C. cephalareticulatus (Shen & Lim, 1975) and the Blue Vermiculate Angelfish C. chrysocephalus (Bleeker, 1854). In southern Japan the Maze Angelfish will co-occur and mix with the Blue-striped Angelfish.

Status:      These fish are not listed on the IUCN Red List.

Description:      The Blue-striped Angelfish or Blue-lined Angelfish adult is an overall brown to brownish yellow with blue horizontal lines on their sides. Many of these lines are curving and some may be interrupted. The caudal fin is entirely yellow with a narrow blue edge. The pelvic fins are yellow, the pectoral fins duskier with a black spot encircled by blue at base, and the dorsal and anal fins are a blackish blue with several narrower blue lines. The face and head are yellowish brown with a mix of blue stripes and dots.

Blue-striped Angelfish
(Juvenile, 4 cm)
Collected in Miyazaki, Japan
Photo Courtesy: Hiroyuki Tanaka

     Juveniles are black overall and have a vertical yellow band behind the eye extending from the forehead to the chest. They have blue lines on the sides that will increase in number with growth, a yellow rim on the dorsal and anal fins, and a narrow yellow stripe on the snout and lips.

     No sexual differences are known, but it is often reported by divers in southern Japan that the species is seen swimming in pairs.

Length/Diameter of fish:      Adults reach 9.7 inches (22 cm).

Maintenance difficulty:      Juvenile Blue-striped Angelfish are fairly easily maintained in the aquarium but almost all of the large individuals need special care. Also those obtained large often refuse any food except some live corals, sponges, and small invertebrates.
     The water quality of the aquarium must be well maintained. Chaetodontoplus members can suffer from ‘ich' (white spot disease) or other diseases. They can be treated successfully with medicine or copper drugs, but they have a weakness for drugs or sudden changes in water conditions. In the wild a cleaner wrasse (Labroides spp.) will pick parasites off the body.

    Diseases that marine angelfish are susceptible to:
Marine Ich (white spot disease), Marine Velvet, and Lymphocystis (a viral infection).

Foods:      The Blue-striped Angelfish or Blue-lined Angelfish are omnivores, in the wild they eat primarily sponges and tunicates, but have also been observed nibbling on macroalgae, black corals, and sea whips. Provide a varied diet. Juveniles often accept dried flakes, meaty foods, frozen prepared diets for sponge and algae eaters, frozen shrimps, and may also feed on tablets. Feed these fish at least twice or three times everyday.

Maintenance:      Normal water changes at 10% biweekly or 20% monthly is fine for juveniles, but large specimens need small but frequent water changes especially if the tank is not large.
     For more information see, Marine Aquarium Basics: Maintenance

Aquarium Parameters:
     This fish needs lots of open space for free swimming for large specimens and some crevices for juveniles to hide. No need for a sand bed.
Minimum Tank Length/Size:
     A minimum 50 gallon (189 liters) or larger. A male and female may be housed together as long as they are introduced at the same time and the tank is quite large, 125 gallons or more.
Light: Recommended light levels
     Can be kept in sunlight conditions, but prefers to be kept in a dim-light tank.
Temperature:
     This species dwells in subtropical to temperate areas. Temperatures between 65 - 75 ° F (18 - 24 ° C) will serve them well, but temperatures higher than 82 ° F (28 ° C) or below 60 ° F (16 ° C) would not be good.
Water Movement: Weak, Moderate, Strong
     No special requirements, but it needs the flow slow enough so that it can feed.
Water Region: Top, Middle, Bottom
     They will spend time in all parts of the aquarium.

Social Behaviors:      The Blue-striped Angelfish is not a reef safe fish as it will feed on some corals and sessile inverts, so will do best in a community tank. The Chaetodontoplus angels are slightly less aggressive some of the other angelfish, though that can vary from one individual to another. An adult and a juvenile can co-habitat fine but not two juveniles together. A pair may also be okay together if the aquarium is very large and there are crevices for retreat, but the pair must be introduced to the aquarium at the same time. Larger and territorial angelfishes like Pomacanthus are not recommended as tank mates.
     Smaller and non-aggressive fish like cardinalfish, gobies, tilefish, damselfish, butterflyfish, fairy basslets, wrasses, etc. will be good tank mates. Very territorial fishes such as dottybacks or meat-feeders like big Basses, etc. are not recommended as tank mates.

Sex: Sexual differences:      No sexual differences are known, but it is often reported by divers in southern Japan that the species is seen swimming in pairs.

Breeding/Reproduction:      Not yet bred in captivity. In their natural habitat they have been observed in pairs. In captivity they have been reported to court and spawn, with a known spawning in at least one public aquarium. In courtship the male displays in front of the female with fins erect, and sometimes will lay down on his side on the substrate. Like other angelfish, in the final stages before actual spawning the male exhibits a "soaring" display.
     For more information see, Marine Fish Breeding

Availability:     The Blue-striped Angelfish or Blue-lined Angelfish will appear at retailers on occasion. Young specimens adapt to captivity best so when you see a juvenile it is a good opportunity to get one.
     Most specimens from Japan will be obtainable at a prices starting around $50.00 USD and up, but those shipped from Vietnam (all of which are too large to acclimate well) command a high price of around $200.00 USD or more, and specimens from Vietnam are rare.

Author: Hiroyuki Tanaka
Additional Information: Clarice Brough, CFS