Banggai cardinalfish (Pterapogon kauderni)

GenusPterapogon (1)
SizeLength: Up to 80 mm (1)

Classified as Endangered (EN) on the IUCN Red List (1).

With its striking patterning and elegant, elongated fins, it is easy to understand why the Banggai cardinalfish has become extremely popular with the aquarium trade (2). The shiny, silvery body is distinctively marked with three vertical black bars, one running down the head and the other two down the fish’s flanks. Between the bars on the body, the Banggai cardinalfish is marked with white dots, which form a pattern unique to each individual. The front dorsal fin, is tasselled, and the second dorsal fin, anal fin and caudal fin are elongated. The fins all have black markings and, with the exception of the front dorsal fin, are also marked with white dots (1).

The Banggai cardinalfish has an extremely limited geographic range (1), and is found only at select sites around the coasts of 33 islands in the Banggai Archipelago, an island group in Indonesia. A small population was also artificially introduced into the Lembeh strait in 2000, some 400 kilometres north-west of its natural range. The total suitable habitat available within the Banggai cardinalfish’s range amounts to a mere 34 square kilometres (2).

A tropical marine species, the Banggai cardinalfish occupies shallow coastal waters at depths between 1.5 to 5 metres, but is rarely found deeper than 2.5 m, and water temperatures ranging from 28 to 31 degrees Celsius (2). It generally prefers calmer waters, though some populations live in areas with strong surges and currents. Living near the seabed, this species is most commonly found around coral reefs, but also around seagrass beds and, less commonly, over small, open patches of rubble. Within these environments, it is normally found in association with various bottom-dwelling organisms, such as sea urchins, sea anemones, and branching corals (1) (3).

The Banggai cardinalfish is remarkable among marine fishes for the extreme levels of genetic diversity found between its populations. Populations as little as five kilometres apart are as genetically distinct as separate species, a consequence of the Banggai cardinalfish’s highly limited dispersal capability, the strong currents and deep channels between the islands preventing interaction with populations at other sites (4) (5) (6).

Banggai cardinalfish live in small groups of usually between 1 and 6 individuals, though a group of 500 has been recorded (1). Reproduction in the Banggai cardinalfish begins with the female choosing a male; the pair then separate from the group and establish a territory, aggressively defending it from other fish that come too close. The female then initiates an unusual courtship ritual, swimming alongside the male, bodies touching, and making a trembling motion. This behaviour occurs repeatedly on both sides, with the only signs of the male’s receptivity being a darkening of the lower jaw and an occasional opening of the mouth (7). After several hours of this behaviour, the female spawns a mass of up to 75 large eggs (a very small number for a marine fish). These are quickly swallowed by the male, and brooded in a special pouch inside the mouth (2). The eggs take about 20 days to hatch, after which, the newly hatched embryos continue to develop in the male’s mouth pouch. After a further 10 days, when the young have reached around five to six millimetres in length, they are released (1). During the 30-day brooding period the male does not eat, and attends to the brood by frequently turning the eggs and expelling dead eggs and embryos. Once the brood are released, the male does not interact with them anymore (7). The small juveniles are most commonly found sheltering around sea anemones for protection. However, older juveniles and adults are more commonly found around branching corals and sea urchins (2) (8).

The Banggai cardinalfish feeds principally upon tiny planktonic crustaceans, with copepods, in particular, making up about 80 percent of the diet. Nevertheless, this species is an opportunistic feeder, and will take a variety of small organisms from the water column and the seabed, including marine worms, molluscs and fish larvae. In addition, it plays an important role in its environment by preying on the larval stages of coral reef fishes’ parasites (9). The Banggai cardinalfish is preyed upon by various species, such as the crocodile-fish (Cymbacephalus beauforti), various lion-fish species (genus Pterois) and the grouper (Epinephelus merra) (1). This species may live for two years in the wild (2)

The major threat to the Banggai cardinalfish is overexploitation for the aquarium trade (10) (11). There are currently three main collection centres in the Banggai Archipelago, where as many as 100,000 individuals may be caught monthly from around the islands, before being shipped to Bali and North Sulawesi to be sold to international exporters. During shipping, which may take between 24 hours and 5 days, up to 30 percent of the fish may die, with similar quantities frequently being rejected due to poor condition. A study of the Banggai cardinalfish fishery revealed that during 2007, at least 1,000,000 individuals were caught, which given that the fish’s total population in this year was estimated to be 2,200,000 individuals, is a serious cause for concern. Indeed, the increasing levels of exploitation have led to the extermination of two local populations, while the global population of the Banggai cardinalfish is believed to have been reduced to about 10 percent of its historical abundance and range (11).

In addition to overexploitation, the Banggai cardinalfish is threatened by habitat destruction as a result of the illegal use of dynamite and cyanide in the fishing of other species. Recently, a viral disease has also emerged in wild-caught individuals kept in captivity, but it is not yet clear how much of a threat this virus will pose to wild populations (2) (11).

A successful captive-breeding program has been developed by the New Jersey Academy for Aquatic Sciences. However, the aquarium trade has not yet made any significant efforts to replace wild-caught fish with captive-bred fish (1).

Although a proposal was made to include the Banggai cardinalfish on Appendix II of the Convention on International Trade in Endangered Species (CITES), thereby regulating international trade, it was rejected due to a conflict of interest (11). Nevertheless, without some kind of action to mitigate the threats to this imperilled species, it faces a very high risk of extinction (1) (11).

The only conservation initiative in the Banggai Archipelago is the Banggai Conservation Project, a collaboration between the Indonesian non-governmental organisation, Yayasan Pemerhati Linkungan, and the New Jersey Academy for Aquatic Sciences. Ongoing since 2004, the project aims to create marine protected areas in two zones within the Banggai archipelago. Despite having the approval of the local government and the support of local communities, funding is still required in order to put this vital project into action, which will help protect and conserve this unique species for future generations (12) (13).

For more information on the Banggai Conservation Project see:


Authenticated (13/04/2009) by Dr Alejandro A. Vagelli, Director of Science and Conservation, New Jersey Academy for Aquatic Sciences.

  1. IUCN Red List (September, 2008)
  2. CITES. (2007) Consideration of Proposals for Amendment of Appendices I and II. Proposal 19. Fourteenth meeting of the Conference of the Parties, The Hague. Available at:
  3. Vagelli, A. and Erdmann, M. (2002) First comprehensive ecological survey of the Banggai cardinalfish, Pterapogon kauderni. Environmental Biology of Fish, 63: 1 - 8.
  4. IUCN Species Fact Sheet (September, 2008)
  5. Bernardi, G. and Vagelli, A. (2004) Population structure in Banggai Cardinalfish, Pterapogon kauderni, a coral reef fish that lacks a pelagic larval phase. Marine Biology, 145: 803 - 810.
  6. Vagelli, A., Burford, M. and Bernardi, G. (2009) Fine scale dispersal in Banggai Cardinalfish, Pterapogon kauderni, a coral reef species lacking a pelagic larval phase. Marine Genomics, 1: 129 - 134.
  7. Vagelli, A. (1999) The reproductive biology and early ontogeny of the mouthbrooding Banggai cardinalfish, Pterapogon kauderni (Perciformes, Apogonidae). Environmental Biology of Fishes, 56: 79 - 92.
  8. Vagelli, A.A. (2004) Ontogenetic shift in habitat preference by Pterapogon kauderni, a Shallow Water Coral Reef Apogonid, with Direct Development. Copeia, 2004: 364 - 369.
  9. Vagelli, A. (2002) Notes on the Biology, Geographic Distribution and Conservation status of the Banggai cardinalfish, Pterapogon kauderni Koumans 1933, with comments on captive breeding techniques. Tropical Fish Hobbyist, 51: 84 - 88.
  10. Lunn, K. and Moreau, M. (2004) Unmonitored trade in marine ornamental fishes: The case of Indonesia’s Banggai cardinalfish (Pterapogon kauderni). Coral Reefs, 23: 344 - 351.
  11. Vagelli, A.A. (2008) The unfortunate journey of Pterapogon kauderni, a remarkable apogonid endangered by the international ornamental fish trade, and its case in CITES. SPC Live Reef Fish Bulletin, 18: 17 - 28.
  12. Vagelli, A.A. (2005) The Banggai Conservation Project: Working for the creation of a network of small marine sanctuaries in the Banggai Archipelago, Indonesia. American Zoo and Aquarium Association Communiqué, 2005: 47 - 48.
  13. IUCN/TRAFFIC. (2007) Analyses of the Proposals to Amend the CITES Appendices. Fourteenth meeting of the Conference of the Parties, The Hague.