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Phylum Chordata > Subphylum Vertebrata > fishes > Family Pomacentridae
Amphiprion sp.
Family Pomacentridae
updated Oct 2016

if you learn only 3 things about them ...
Anemonefish need their anemones. Do not disturb them or their anemones.
One anemone may be home to many anemonefishes.
These fishes are threatened by over-collection for the aquarium trade. Don't keep Nemo in your home, he belongs in the ocean.

Where seen? Made famous by the cartoon "Finding Nemo", these fishes are a delight and the highlight of a trip. Anemonefishes are commonly seen among the sea anemones of our Southern shores. At low tide, they may shelter in a pool further away while their anemone is left high and dry.

What are anemonefishes? Anemonefishes belong to the Family Pomacentridae. Anemonefishes are in the subgroup Amphiprioninae in this family.

To about 9cm. Besides being really cute and colourful, the most amazing feature of anemonefishes is that they can live happily among the tentacles of sea anemones that would otherwise kill (and eat) other fishes, including larger ones.

The anemonefish is believed to develop this immunity slowly. To acclimatise to a host anemone, an anemonefish will at first gingerly swim among the tentacles, touching it with its fins then withdrawing rapidly, in an elaborate dance. Only after some time will the fish be able to dive right in among the tentacles. One theory is that the fish smears mucus from the anemone all over itself. In this way, to the anemone, the fish is just another part of the anemone. Thus the sea anemone doesn't sting the fish. Another theory is that the mucus of the fish (all fishes are covered in mucus) lacks substances that trigger a sea anemone to discharge its stingers.

Experiments suggest anemonefishes may protect their host anemones from predatory fishes such as butterflyfish. They may also clean the anemone of parasites and remove dead tissues of the sea anemone. Their swimming action may also increase water circulation around the sea anemone and remove sediments that would foul the sea anemone. Some studies suggest anemonefishes attract other fishes that are captured and eaten by the sea anemone.

In return, the anemonefishes enjoy protection among the tentacles of the sea anemone and may also feed on leftovers of prey captured by the host sea anemone.
In captivity, the anemonefish and anemone can survive well without each other. However, in the wild, the anemonefish being poor swimmers, are soon eaten by larger fishes. The anemonefish also needs the protection of a sea anemone to lay its eggs, usually under the oral disk of the anemone.

What do they eat? Anemonefishes eat mainly plankton. Some also graze algae from the surface or gathered from the water.

Amazing gender switch: Anemonefishes can change their gender. Often, a sea anemone will be home to several anemonefishes of the same species. Usually the largest anemonefish in the group is the female and the next largest is the functioning male (although he is often less than half her size). Besides the difference in size, there are generally no differences in patterns or colours between the genders. If the female is removed from the group, the male becomes a female and the next largest becomes the dominant male. In this way, anemonefishes can continue to breed throughout the year. Small anemonefishes are not necessarily younger, just lower in the "pecking order". It is believed they remain small because of the constant harassment by the dominant pair.

Anemonefish babies: Anemonefishes form permanent pair bonds that sometimes last for years. The male usually selects the nest site, often a bare rock near the sea anemone which he clears of seaweeds and other rubbish. The female eventually helps out. After the female lays on the site, the male scrupulously guards and cares for the eggs, keeping them well aerated and clean. The female helps out sometimes. Larval fish that hatch from the eggs drift with plankton for 8-12 days before settling to the bottom and changing into a juvenile fish.

How does the baby fish find an anemone host? Each species of anemonefish lives in a specific species of sea anemone. Some species apparently follow chemicals released by the suitable host anemone, others find one by sight, for yet others, it is apparently simply by chance. One study suggests the fishes use the smell of leaves from the rainforest to find their way to a suitable habitat. Even so, this is not the end of the problems for the young fish. If the anemone already has resident anemonefishes, the new fish is usually bullied by the residents and may even be driven away.

False Clown? Our clown anemonefish (Amphiprion ocellaris) is called the False clown anemonefish, to distinguish it from another closely related fish called the Clown anemonefish (Amphiprion percula) which lacks the black bands on the top edge of the dorsal fin.

Human uses:
Clown anemonefishes are among the most popular live aquarium fishes. Although captive bred specimens are commercially available, these are far more expensive than wild caught specimens. Thus, clown anemonefishes continue to be unsustainably harvested from the wild. The pressure on wild populations has risen tremendously due to the huge demand following the popular "Finding Nemo" cartoon.

Status and threats: All our anemonefishes are 'Vulnerable' in the Red List of threatened animals of Singapore. Like other creatures of the intertidal zone, they are affected by human activities such as reclamation and pollution. Poaching by hobbyists and overfishing can also have an impact on local populations. According to the Singapore Red Data Book, "habitat protection and strict policing against illegal collection are required" to conserve our anemonefishes.

False clown anemonefish
Pulau Hantu, Nov 03

Tomato anemonefish
Pulau Semakau, Aug 08

Anemonefishes in three different sizes.
Kusu Island, May 05

A pair of very different sized
fishes in the same anemone.
Sisters Island, Jul 07

Eggs laid near the host sea anemone.
Terumbu Raya, Jun 15

Photo shared by Toh Chay Hoon on facebook.

Often the same anemone may also be
home to anemoneshrimps!
Pulau Hantu, Jul 07

Anemonefishes on Singapore shores

Amphiprion species recorded for Singapore
from Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
*additions from from Ng, P. K. L. & Y. C. Wee, 1994. The Singapore Red Data Book: Threatened Plants and Animals of Singapore.
in red are those listed among the threatened animals of Singapore
from Davison, G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore Red Data Book: Threatened plants and animals of Singapore.
**from WORMS
+Other additions (Singapore Biodiversity Records, etc)

  Family Pomacentridae
  Amphiprion clarkii (Clark's anemonefish) (VU: Vulnerable)
Amphiprion frenatus (Tomato anemonefish) (VU: Vulnerable)
Amphiprion ocellaris
(False clown anemonefish) (VU: Vulnerable)
Amphiprion polymnus
(Saddleback anemonefish) (VU: Vulnerable)
Amphiprion perideraion
(Pink skunk anemonefish) (VU: Vulnerable)

  • Toh Chay Hoon. 11 April 2014. Spawn of the saddleback anemonefish. Singapore Biodiversity Records 2014: 96.
  • Jeffrey K. Y. Low. 2013. More noteworthy fishes observed in the Singapore Straits. Nature in Singapore, 6: 31–37.
  • Toh Chay Hoon. 20 December 2013. Shrimps and saddleback anemonefish on carpet anemone off Pulau Hantu: Holthuis’s anemone shrimp, Periclimenes holthuisi and Saddleback anemonefish, Amphiprion polymnus. Singapore Biodiversity Records 2013: 126-127.
  • Chou, L. M., 1998. A Guide to the Coral Reef Life of Singapore. Singapore Science Centre. 128 pages.
  • Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore. National Council on the Environment. 163pp.
  • Davison, G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore Red Data Book: Threatened plants and animals of Singapore. Nature Society (Singapore). 285 pp.
  • Allen, Gerry, 2000. Marine Fishes of South-East Asia: A Field Guide for Anglers and Divers. Periplus Editions. 292 pp.
  • Kuiter, Rudie H. 2002. Guide to Sea Fishes of Australia: A Comprehensive Reference for Divers & Fishermen New Holland Publishers. 434pp.
  • Lieske, Ewald and Robert Myers. 2001. Coral Reef Fishes of the World Periplus Editions. 400pp.
  • Lim, S., P. Ng, L. Tan, & W. Y. Chin, 1994. Rhythm of the Sea: The Life and Times of Labrador Beach. Division of Biology, School of Science, Nanyang Technological University & Department of Zoology, the National University of Singapore. 160 pp.
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