Amphiprion OcellarisCuvier, 1830
|Amphiprion ocellaris at Sultan Shoal, Singapore (Image by Joy Wong)|
Did you know that the false clownfish Amphiprion ocellaris, star of the popular Disney Pixar film Finding Nemo can be found in Singapore? Perhaps one of the most enigmatic reef fish, everyone can identify the false clownfish at first glance. Bright orange and always swimming about near an anemone, it is relatively common and easy-to-spot for beginners to SCUBA diving as well. Besides the false clownfish, this species is also known as the false clown anemonefish, ocellaris clownfish, common clownfish, false percula clownfish and nemofish.
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|Marlin and Dory from the popular Disney film Finding Nemo. Image from Buena Vista Pictures, permission pending.|
. For more details about this unique relationship with the anemonefish, refer to the section on Symbiosis.
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False clownfish living among anemone in the seas of Singapore. Video by Joy Wong.
In Singapore, the false clownfish is seen in large sea anemones, namely the Gigantic Sea Anemone (Stichodactyla gigantea) and the Magnificent Sea Anemone (Heteractis magnifica) which are found in intertidal areas and reefs along the Southern Islands
. Elsewhere, the false clownfish has also been recorded in the Mertens’ Sea Anemone (Stichodactyla mertensii).
|Map showing the locations where the false clownfish has been recorded in Singapore. Image generated by Joy Wong with Google Maps.|
Allen, G.R., R. Steene, and P. Humann, Reef Fish Identification: Tropical Pacific. 2003: New World Publications.
|Black morph of the false clownfish found in Darwin, Australia. Image by ORA, used with permission.|
|Map of distribution of False Clownfish. Image adapted from Aquamaps, used under Creative Commons.|
In Singapore, there are four other recorded species of clownfish besides the false clownfish (Amphiprion ocellaris), namely Clark's anemonefish (Amphiprion clarkii), the tomato anemonefish (Amphiprion frenatus), the saddleback anemonefish (Amphiprion polymnus) and the pink anemonefish (Amphiprion perideraion). These fish can be identified based on the number of bands around their body and colouration, as well as their host anemones. Here is a quick visual guide to help you tell your clownfishes apart! For a more scientific description of the false clownfish, refer to the section on Diagnosis below. For reliable descriptions and images of the anemone, please follow the links to pages from this Taxo4254 database, Wild Singapore and Hexacorallians of the World (H. aurora & H. malu).
|Image||Common name||Scientific name|
|False clown anemonefish||Ampriprion ocellaris||Orange with 3 white bands. Middle band has forward-projecting bulge. Bands and fins have variable amounts of black edging.||Heteractis magnifica, Stichodactyla gigantea, Stichodactyla mertensii|
|Clark's anemonefish||Amphiprion clarkii||Black with 2 white bands, white or yellow tail with abrupt boundary. Fins variably black to yellow-orange||Heteractis magnifica, Heteractis crispa, Heteractis aurora, Heteractis malu, Entacmaea quadricolor, |
Stichodactyla gigantea, Stichodactyla mertensii, Stichodactyla haddoni, Macrodactyla doreensis, Cryptodendrum adhaesivum
|Tomato anemonefish||Amphiprion frenatus||Orange to red with single white or pale bluish head bar. Males considerably smaller than female. Females are primarily black on sides with red snout, breast, belly and fins. Juveniles have 2 to 3 white bars||Entacmaea quadricolor|
|Pink anemonefish||Amphiprion perideraion||Pink to orange; narrow white head bar, and white dorsal stripe from between eyes to tail||Heteractis magnifica, Heteractis crispa, Stichodactyla gigantea, Macrodactyla doreensis|
|Saddleback anemonefish||Amphiprion polymnus||Varying amounts of black to dark brown and yellow-orange, white head bar and broad somewhat forward slanting mid-body bar, white edging on black tail||Stichodactyla haddoni, Heteractis magnifica, Heteractis crispa|
Symbiosis with Anemone
Mebs, D., Chemical biology of the mutualistic relationships of sea anemones with fish and crustaceans. Toxicon, 2009. 54.
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Anemones attacking fishes. Video from YouTube, used under Standard YouTube licence.
However, this association with anemones are not solely in the clownfish’s benefit. An experiment conducted in the wild showed that anemones hosting clownfish have growth and survival rates that are significantly higher than that of anemones without clownfish. They are also able to undergo asexual reproduction at higher frequencies. The enhanced survival rate can be attributed to the protection the anemone receives from the clownfish, as clownfish would aggressively chase after butterflyfish and other predators of anemone which have been seen biting tentacles of their host anemone. Other than protection, clownfish also provide an added source of nitrogen through its excrement, which could be incredibly beneficial in the nitrogen-scarce coral reef ecosystem
FUN FACT! In Finding Nemo, Coral, Marlin's wife, would actually be quite domineering and aggressive towards Marlin, instead of the caring and loving relationship portrayed in the film.
Besides that, if the female of the group dies or is removed, the reproducing male changes sex to become female, while the second largest male rises in rank to become the reproducing male
FUN FACT! What actually should have happened in Finding Nemo was that Marlin would likely change his gender to become female, and Nemo would rise the ranks and become the reproducing male. Talk about the ultimate plot twist!
|Life cycle of clownfish. Image from Fautin and Allen .|
. The male continues the spawning process by passing over and fertilising the eggs. Eggs are held onto the substrate by a fine thread, and the male cares for the eggs by fanning them with his fins to provide aeration.
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Eggs of the saddleback clownfish, Amphiprion polymnus, in Anilao, Philippines. Male fanning behaviour can be clearly observed. Video from YouTube, used under Standard YouTube licence.
Incubation depends on the temperature of the water, cooler water would result in longer incubation time, but it generally takes 6-8 days before the eggs hatch
Davison, G. W. H., P. K. L. Ng & H. C. Ho, 2008. The Singapore Red Data Book: Threatened Plants and Animals of Singapore. 2nd edition. Nature Society (Singapore), Singapore. 154 pp.
|Anemonefish at SEA Aquarium. Image by Joy Wong|
Species A. ocellaris Cuvier, 1830
Amphiprion bicolor Castelnau, 1873
Amphiprion melanurus Cuvier, 1830
Original description of Amphiprion ocellaris in Histoire naturelle des poissons Volume 5.
Translation from French:
Mr Valenciennes observed in the office of the Zoological Society of London a little amphiprion from Sumatra, similar to a Perchot (A. percula), but the bands are not lined with black. The caudal fin is lined with white, brown at the tip, and wears down a large white occelus. The pectoral fin is brown, with a white border. Its length is three quarters of an inch.
|A false clownfish. Image by Aden Ip, used with permission; annotations by Joy Wong.|
Timm, J. and M. Kochzius, Geological history and oceanography of the Indo‐Malay Archipelago shape the genetic population structure in the false clown anemonefish (Amphiprion ocellaris). Molecular Ecology, 2008. 17(18): p. 3999-4014.
Distribution patterns and sample sites of A. ocellaris (light grey area, stars) and A. percula (dark grey area, circles) in the Indo-Malay Archipelago. Dominant currents are added. Image from Timm et al., 2008
Timm, J., M. Figiel, and M. Kochzius, Contrasting patterns in species boundaries and evolution of anemonefishes (Amphiprioninae, Pomacentridae) in the centre of marine biodiversity. Molecular Phylogenetics and Evolution, 2008. 49(1): p. 268-276.
, permission pending.
(a) Exposed land masses at present levels (tan) and at sea levels 60m below (green). (b) Exposed land mass at Last Glacial Maximum. Red annotation indicates area which separated ranges of A. percula and A. ocellaris. Refer to previous figure for range of each species. Figure from Ludt & Rocha, 2015
Allen, G.R., The anemonefishes: their classification and biology. 1975: T.F.H. Publications.
Morphology-based phylogenetic tree. Subgenus Actinicola, containing A. ocellaris and A. percular annotated. Image by Allen, 1975
. The tree is generally well supported for recent divergences, but not as strong for the intermediate divergences.
Phylogenetic tree of 22 species of clownfish from analyses of mitochondrial cytochrome b gene, 16S ribosomal RNA gene and D-loop. Tree corresponds to the consensus topology of 190,000 trees sampled from a Bayesian analysis. Maximum parsimony bootstrap values are congruent and indicated (middle = equally weighted bases, bottom = rescaled consistency index). Subgenus Actinicola highlighted. Image from Santini & Polacco, 2006