Comet

When C. altivelis is threatened, the fish puts its head into holes in reefs and changes the shape of its tail by expanding its caudal, anal and dorsal fins (McCosker, 1977). By doing this, the ocellus on its dorsal fin is fully visible and resembles an eye (Froese and Pauly, 2002; Randall, 1997; Randall, 1986; McCosker, 1977; Wood, 2002). Expanding its fins also exposes the gap between the dorsal and anal fin, which resembles a mouth (Randall, 1997). The shape of the fins combined with the ocellus and gap make the fish look like Gymnothorax meleagris, the white-spotted moray eel, which is much more dangerous to the would-be predators, and they often leave the comet alone (Froese and Pauly, 2002; Michael, 2002; Randall, 1997; Randall, 1986; Wood, 1945).

Calloplesiops altivelis was previously known as Barrosia barrosi and was thought only to be in shallow water located in the Island of Nias in Indonesia (Smith, 1969). Today this uncommon fish is also known as Steindachner and Marine betta (Randall, 1986; McCosker, 1977).

Perception Channels: tactile ; chemical

US Migratory Bird Act: no special status

US Federal List: no special status

CITES: no special status

When comets first hatch they are dark colored, approximately 3 cm long, and able to feed immediatly (Michael, 2002). After the first two weeks of growth, their bodies lose pigmentation, turning white. At two months they begin to develop white spots on the dark head, and at about seven months the drab brown color spreads to the rest of the body (Field and Field, 1998; Michael, 2002). During the post juvenile stage of C. altivelis development, its sex is indeterminate (Field and Field, 1998).

The comet is not known to have any negative impacts on humans.

Often C. altivelis is kept in aquariums as pets (Froese and Pauly, 2002).

Positive Impacts: pet trade

The comet acts as a predator on smaller fish and crustaceans in the reef environment (Field and Field, 1998). It also serves as a source of food for larger predators.

Unlike most members of Plesiopidae, C. altivelis does not feed on algae, but is instead a meat eater. Though harmless to humans, it is a nocturnal seeker, hunting crustaceans and small fish (Field and Field, 1998; Wood, 1945).

Animal Foods: fish; aquatic crustaceans

Primary Diet: carnivore (Piscivore , Eats non-insect arthropods)

Calloplesiops altivelis lives in the Indo-west Pacific, including areas such as East Africa, the Red Sea, Tonga, and the Line Islands (Wood, 1945; Randall, 1997). It also occupies areas in the Philippines eastward towards Mozambique and in the East Indies (Wheeler, 1975; McCosker, 1977).

Biogeographic Regions: australian (Native ); pacific ocean (Native )

C. altivelis inhabits tropical, coral reefs and is often found during the day hiding in caves and crevices (Allen, 1997; Randall, 1986). During the night, C. altivelis emerges from its hiding place and swims along the coral reef. It is found in water levels ranging from 4 to 30 meters with water temperatures between 24-26°C (McCosker, 1977; Froese and Pauly, 2002).

Range depth: 4 to 30 m.

Average depth: 15.5 m.

Habitat Regions: tropical

Aquatic Biomes: reef

Comets are dark brown to black with one white spot per scale (Froese and Pauly, 2002; Randall, 1986; Schultz, 1901). The white spots are found on its body, head and fins, except for the median and pelvic fins which have small blue spots and are lacking scales. The pectoral fin is clear with visible, yellow rays (Randall, 1986). Located at the base of the last dorsal rays is a black ocellus. An anterior lateral line, which includes 20-30 scales, ends beneath the rear base of the dorsal fin (Froese and Pauly, 2002; Randall, 1997; Shen, 1986; Wheeler, 1975). The dorsal ray is slightly elevated and contains a total of 11 dorsal spines and 8 to 9 soft rays, while the anal fin is also slightly elevated and contains a total of 3 spines and 9 soft rays. The caudal fin is relatively elongate (Froese and Pauly, 2002; Randall, 1997). C. altivelis is noted for being unique among its family members because of the sharp angle of its preoperculum and its small upper jaw (Wheeler, 1975). The fish can reach 16 cm in length (Randall, 1997; Wheeler, 1975).

Range length: 16 (high) cm.

Other Physical Features: bilateral symmetry

Little is known of comet reproduction in the wild. In captivity, a single pair will mate when given rocky hiding places. Courtship and spawning take place among the crevices and caves. The female deposits a brown egg mass, using sticky threads to attach her hundreds of eggs to a protected rocky surface (Michael, 2002).

Breeding season: unknown

Average gestation period: 5-6 days.

Key Reproductive Features: iteroparous ; sexual

Male C. altivelis protect the egg mass until hatching.

Parental Investment: male parental care

Eggs are guarded by the male parent (Ref. 205).

Characterized by having tubed lateral-line scales 19-20+9-10; depth of body 2.5-2.7 in SL; dorsal and anal fins elevated posteriorly; rounded caudal fin. The false eye which is actually the dorsal fin ocellus confuses predators because it poses an inverted image of a fish. When alarmed, this fish will poke its head into a hole and expose its tail end which mimics the head of the moray eel (Ref. 9710). Head and body brownish black with small pale blue spots; vertical and pelvic fins dark orange-brown, with many small blue spots; blue ringed black ocellus above base of last 3 dorsal rays; yellow spots at base of upper caudal rays; pectoral rays bright yellow, fin membrane transparent (Ref. 10430).

Dorsal spines (total): 11; Dorsal soft rays (total): 8 - 10; Analspines: 3; Analsoft rays: 9

Inhabits coral reefs (Ref. 58534); adults found near in caves and crevices along drop-offs (Ref. 8631). A nocturnal species that hides under ledges and in holes by day (Ref. 9710).

Adults are found near reefs, and in caves and crevices along drop-offs (Ref. 8631). A nocturnal species that hides under ledges and in holes by day (Ref. 9710). They possess a false eye which is actually the dorsal fin ocellus confuses predators because it poses an inverted image of a fish. When alarmed, this fish will poke it's head into a hole and expose its tail end which mimics the head of the moray eel (Ref. 9710). Eggs are guarded by the male parent (Ref. 205). Have been reared in captivity (Ref. 35426). Reported to be living in a marine aquarium for 8 years and 6 months (Danilo Ronchi, Italy, pers.comm. 2014 February).

aquarium: public aquariums

分布於印度-太平洋區，西起東非、紅海，東至萊恩群島，北至日本南部，南迄澳洲。台灣主要分布於南部海域。

小型魚類，不具食用價值，唯體色豔麗，為海水觀賞魚。

體延長而側扁，頭部圓。眼中大。吻短。口中型，可伸縮；上下頜等長，具有絨毛狀或犬齒，鋤骨無齒。鱗大，頭部圓鱗，體為櫛鱗；體側之側線兩條：在上方者接近背鰭基部；另一條則近尾部中央，有孔鱗數分別為19-20 / 9-10。背鰭單一，硬棘部較長且鰭膜間具缺刻，具硬棘XI，軟條9-10；臀鰭硬棘III，軟條9-10；背鰭和臀鰭越向後者長度越長；胸鰭圓；腹鰭硬棘I，軟條4，特別發達，經常延長且粗壯；尾鰭尖形。頭部、體部及除胸鰭外之各鰭皆為黑褐色，且遍布小而淡藍色的點。背鰭最末3枚軟條上有一似眼徑大小之斑點；胸鰭略帶黃色而鰭膜透明。

主要棲息於珊瑚礁海域中。夜行性。白天躲藏於洞穴或石縫間，晚上出來活動。在遇驚嚇時，具有頭部先入洞，而尾部朝外，各鰭伸展露出背鰭末端眼狀斑來模仿海鰻之欺敵行為。

The comet or marine betta (Calloplesiops altivelis) is a species of reef-associated tropical marine fish in the longfin family Plesiopidae, most commonly found between 3 and 50 m deep. It is native to the Indo-Pacific Ocean. It can reach a maximum length of 20 cm.