Swallowtail Damselfish

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Swallowtail Damselfish
Swallowtail damselfish (Acanthochromis polyacanthus), morph from the Great Barrier Reef

Swallowtail damselfish ( Acanthochromis polyacanthus ), morph from the Great Barrier Reef

Systematics
Perch relatives (Percomorphaceae)
Ovalentaria
incertae sedis
Family : Damselfish (Pomacentridae)
Genre : Acanthochromis
Type : Swallowtail Damselfish
Scientific name of the  genus
Acanthochromis
Gill , 1863
Scientific name of the  species
Acanthochromis polyacanthus
( Bleeker , 1855)

The swallowtail damselfish ( Acanthochromis polyacanthus ) occurs in the coral reefs of the central tropical Indo-Pacific , around the Indo-Australian archipelago . Its range includes the coastal waters of Indonesia , the Philippines , New Guinea , the Solomon Islands , Vanuatus and the Great Barrier Reef off northeastern Australia. It lives mainly on steep reef edges at depths of one to 65 meters and feeds on zooplankton .

features

Swallowtail Damselfish, Indonesian Morphe

Swallowtail damselfish are eleven to 15 centimeters long. The body length is 1.7 to 2.0 times the body height. In terms of their coloration, they are very variable. The Indonesian population is a solid dark brown, sometimes almost black. The Solomon Islands have a blue-green color form, the dorsal and anal fins of which have a black outer edge. The animals on the Great Barrier Reef are gray-blue with a white abdomen and white caudal fin. Young fish are brown with a golden yellow stripe along the side line . Along the sideline, swallowtail damselfish have 20 to 22 scales. The number of gill trap processes is 21 to 23. The caudal fin is deeply forked.

Fins formula : dorsal XVII / 14–16, anal II / 14–16, pectoral 17–18.

Reproduction

Young fish, photographed near Bunaken

The reproductive behavior of the animals is also known through observations in the aquarium. Like all damselfish, the fish are substrate spawners and stick their spawn to the wall in a cave or hidden niche. A clutch has only 30 to 80 eggs that are very large for fish. The eggs are guarded by the couple and fanned with their fins to supply fresh water.

At a water temperature of 25 ° C, fully developed young fish hatch after 13 to 14 days, a pelagic larval stage or a yolk sac for food in the first days after hatching is missing. If the water temperature is 27 ° C, the duration is shortened to 11 to 12 days. Older reports that the juvenile fish such as the discus cichlids ( Symphysodon ) feed on the epidermis of their parents have not been confirmed. Young fish raised separately from their parents developed completely normally. With a hatch size of five to six millimeters, they are able to eat small planktonic crustaceans and their larvae from day one.

In contrast to almost all other damselfish and almost all other marine fish, the brood care behavior of the parent animals does not cease after the hatchling of the juvenile fish, but they continue it for more than three weeks and guard and protect their young. This behavior, which is almost unique for coral fish, occurs except for the swallowtail damselfish only in the three Altrichthys species, also damselfish and the sister genus of Acanthochromis , and the unrelated white-stripe eel goby ( Pholidichthys leucotaenia ).

literature

Individual evidence

  1. ↑ Bernardi G (2011) Monophyletic origin of brood care in damselfishes. Molecular Phylogenetics and Evolution 59: 245-8. doi: 10.1016 / j.ympev.2010.12.021
  2. ↑ Ellen Thaler : Sea fish with real brood care: Swallowtail damselfish, in DATZ , 9/98, ISSN  1616-3222

Web links

Commons : Acanthochromis polyacanthus  - Collection of images, videos and audio files