''Amphiprion omanensis'' (Oman anemonefish) is a
marine fish belonging to the
family Pomacentridae
Pomacentridae is a family of ray-finned fish, comprising the damselfishes and clownfishes. This family were formerly placed in the order Perciformes but are now regarded as being ''incertae sedis'' in the subseries Ovalentaria in the clade Perco ...
, the
clownfishes and
damselfishes.
Characteristics of Anemonefish
Clownfish or anemonefish are
fishes that, in the wild, form
symbiotic
Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...
mutualisms with
sea anemone
Sea anemones are a group of predation, predatory marine invertebrates of the order (biology), order Actiniaria. Because of their colourful appearance, they are named after the ''Anemone'', a terrestrial flowering plant. Sea anemones are classifi ...
s and are unaffected by the stinging tentacles of the host anemone, see . The sea anemone protects the clownfish from predators, as well as providing food through the scraps left from the anemone's meals and occasional dead anemone tentacles. In return, the clownfish defends the anemone from its predators, and parasites.
Clownfish are small-sized, , and depending on species, they are overall yellow, orange, or a reddish or blackish color, and many show white bars or patches. Within species there may be color variations, most commonly according to distribution, but also based on sex, age and host anemone. Clownfish are found in warmer waters of the
Indian and
Pacific oceans and the
Red Sea in sheltered
reefs or in shallow
lagoons.
In a group of clownfish, there is a strict
dominance hierarchy. The largest and most aggressive fish is female and is found at the top. Only two clownfish, a male and a female, in a group reproduce through
external fertilization. Clownfish are
sequential hermaphrodites
Sequential hermaphroditism (called dichogamy in botany) is a type of hermaphroditism that occurs in many fish, gastropods, and plants. Sequential hermaphroditism occurs when the individual changes its sex at some point in its life. In particular, ...
, meaning that they develop into males first, and when they mature, they become females.
Description
The body of ''A. omanensis'' is dark brown and with two white bars and distinctive forked
caudal fin, which is blackish in juveniles fading to white in adults. The midbody bar is narrow and does not extend onto the
dorsal fin while the headbar is also narrow and usually constricted across the
nape They have 10 dorsal spines, 2 anal spines, 10-17 dorsal soft rays and 14-15 anal soft rays. They reach a maximum length of .
Color variations
None known.
Similar species
The white forked
caudal fin is distinctive, with only ''
A. latifasciatus'' having a forked caudal fin, however A. omanensis has a narrow midbody bar, white caudal fin and black pelvic and anal fins while ''A. latifasciatus'' has a much wider midbody bar, and yellow fins.
Image:Mohéli-Poisson clown.jpg, '' A. latifasciatus'' (Madagascar anemonefish)
Distribution and Habitat
''A. omanensis'' is found in
Oman in the
Arabian Peninsula
The Arabian Peninsula, (; ar, شِبْهُ الْجَزِيرَةِ الْعَرَبِيَّة, , "Arabian Peninsula" or , , "Island of the Arabs") or Arabia, is a peninsula of Western Asia, situated northeast of Africa on the Arabian Plate ...
.. Anemone fish are sedentary and depend on ocean currents for dispersal. As ''A. omanesis'' is confined within a small range, it was used to study long-distance dispersal, from sites apart at either end of its range. Adults provide high levels of parental care to their young that hatch with well-developed swimming and sensory capabilities before embarking on a <3 week
pelagic larval
A larva (; plural larvae ) is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle.
The l ...
phase, during which time they may disperse over long distances. The study found an asymmetrical dispersal pattern between the two regions with a higher occurrence of southward dispersal, consistent with the prevailing currents, with immigration rates of 5.4% in the south and 0.7% in the north.
Host anemones
''A. omanensis'' is associated with the following species of anemone:
*''
Entacmaea quadricolor
Bubble-tip anemone (''Entacmaea quadricolor'') is a species of sea anemone in the family Actiniidae. Like several anemone species, ''E. quadricolor'' can support several anemonefish species, and displays two growth types based on where they li ...
'' Bubble-tip anemone
*''
Heteractis crispa'' Sebae anemone
References
External links
*
*
{{Taxonbar, from=Q1677326
Pomacentridae
omanensis
Fish described in 1991