White-stripe eel goby
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White-stripe eel goby ( Pholidichthys leucotaenia ) |
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| Pholidichthys leucotaenia | ||||||||||||
| Bleeker , 1856 |
The white-stripe eel goby ( Pholidichthys leucotaenia ) is a marine fish that is found in the western Pacific in the area of the southwestern islands of the Philippines , Sulawesis to the Solomon Islands , very hidden in coral reefs up to 20 meters deep. The scientific name indicates similarity (but not necessarily related) with Pholis from the butterfish family ; leucotaenia (Gr.) means "white stripe" and indicates the color of the young fish.
features
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The white-stripe eel goby has an elongated, eel-like body without scales. The dorsal fin has 72 to 79 soft rays , the anal fin 54 to 62. Both have grown together with the rounded caudal fin to form a continuous fin edge. The pectoral fins have 15 rays. The small pelvic fins sit far in front under the pectoral fins and have one hard fin ray and two to three soft ones. In rare cases, they can also be missing. Adult fish are black with pale yellow, winding horizontal stripes. Juvenile animals look completely different and show, with a blue-black basic color, a light white-blue vertical stripe on each side of the body. The juvenile fish resemble those of the striped coral catfish with poisonous fin spines , which they also imitate in their behavior outside the parental cave, a case of Bates' mimicry .
With a length of about ten centimeters they change color and get the pale yellow, vertical rings around the body. White-stripe eel gobies grow to be 20 to 40 centimeters long in the aquarium and up to 57 centimeters in nature.
White-stripe eel gobies that leave their hiding place do not lie on the bottom like gobies , but swim around freely with anguilliform (meandering) movements, but the foremost quarter of the body is held straight and stiff.
Reproduction
The reproduction of the white-stripe eel goby is known from breeding in saltwater aquariums . They spawn hidden in their caves and take care of the juvenile fish for four to five weeks after hatching, an almost unique behavior for coral fish . So far, apart from them, it has only been observed in the non-closely related swallowtail damselfish ( Acanthochromis polyacanthus ) and in the three species of the damselfish genus Altrichthys .
A clutch contains 80 to 500 relatively large eggs. After hatching, the larvae initially stick to the cave wall. They have four glands on their heads and between their eyes that secrete a sticky secretion. After three days you can swim well. When the yolk sac is completely used up, between 15 and 22 days old, the fry will leave the cave during the day and swim out to eat. One parent first chases off foreign fish that are in the cave area, then partially retreats into the shelter and the juvenile fish swim past him into the open. An excursion only lasts 11 to 16 minutes, then the boys retreat back into the cave, possibly after a signal from the parents, who shortly before retreat completely into the cave. A few minutes or even hours can pass between the young fish's excursions, a period of time that is probably dictated by hunger. If strange fish come near the cave entrance, the parent animals ask their flock of young fish to flee into the shelter by clearly snaking in and out. After five to seven days, the fry no longer respond to these signals and the parent animals take the fry in their mouths, a maximum of seven at a time, to bring them back.
During nature observations, groups of young fish were seen catching plankton in the open water, which returned to their parents' den at the end of the day. After about six weeks, the fry are about 2 cm long, the brood care instinct of the parent animals disappears and it can happen that they eat individual fry that are still in the cave area.
Systematics
In addition to Pholidichthys leucotaenia , the Pholidichthyidae family also contains a second, so far largely unexplored species: Pholidichthys anguis (Springer & Larson) was caught in 1989 with a trawl from a depth of between 19 and 70 meters. It lives exclusively in the coastal waters of the Australian Northern Territory on muddy and sandy soil.
literature
- Hans A. Baensch , Helmut Debelius, Horst Moosleitner: Sea water atlas. Volume 1, Mergus, Melle 1997, ISBN 3-88244-110-0 .
- Svein A. Fosså, Alf Jacob Nilsen: Zoogeography - systematics and nomenclature. Fish in the coral reef and for the coral reef aquarium. 2nd Edition. Schmettkamp, Bornheim 1995, ISBN 3-928819-14-3 ( Coral reef aquarium. Volume 3).
- Carol Kaufmann: Nailing the truth about the elusive convict fish proves tougher than expected. In: National Geographic . June 2005.
- Springer, Victor G .; and Freihofer, Warren C .: Study of the monotypic fish family Pholidichthyidae (Perciformes) . In: Smithsonian contributions to zoology . 1976.
Individual evidence
- ↑ White-stripe eel goby on Fishbase.org (English)
- ^ Joseph S. Nelson: Fishes of the World. Wiley, New York 2006, ISBN 0-471-25031-7
- ↑ E. Clark, S. N. Kogge, D. R. Nelson, T. K. Alburn, J. F. Pohle: Burrow distribution and the behavior of the coral reef fish Pholidichtys leucotaenia (Pholidichthyidae). In: aqua, Journal of Ichthyology and Aquatic Biology. December 2006, pages 45-82.
- ↑ Ellen Thaler : Eel gobies and their reproduction in the aquarium. In: Coral. No. 39, 2006
- ↑ W. freshness, L. Gesset: Mysterious Aalgrundeln. In: DATZ . Vol. 59, No. 1
- ↑ Pholidichthys anguis on Fishbase.org (English)
Web links
- White-stripe eel goby on Fishbase.org (English)