Pterapogon kauderni
Banggai cardinalfish
A small cardinalfish (family Apogonidae) that in the wild lives only in the shallow, calm waters of the Banggai archipelago, in Indonesia. 1 3 It is easy to recognise by its black and pale bars, whitish dots and deeply forked tail. 3 The male broods the eggs in his mouth and releases fully formed young: with no larval phase in the open sea, the species moves around very little. 3 4
At a glance
Data from the scientific sources listed at the bottom.
Depth in the wild
1–2 m
Size
up to 8.6 cm
maximum total length, in a female
Temperature in the wild
25–31 °C
Where it lives
Its natural range is the Banggai archipelago, in Indonesia: about 5,000 km² in all, of which only 20-24 km² is suitable habitat around 34 islands. 4 Populations introduced by humans are known at Luwuk, in Palu Bay, in the Lembeh Strait, at Kendari, in northern Bali and at Ambon. 4 They arose from specimens discarded or escaped near trade centres. 5
Conservation
IUCN Red List: endangered (2007). Red List data taken from FishBase and GBIF. 2 6 It is not in the CITES appendices, 7 and a proposal to list it in Appendix II was withdrawn because Indonesia did not support it. 5 Since 2016 the United States has listed it as a threatened species under the Endangered Species Act 3 and the European Union lists it in Annex D. 7 According to estimates cited by NOAA, numbers fell from 2.4 to 1.4 million and the area occupied from 34 to 20 km². Between 500,000 and 900,000 are caught every year; the removal of sea urchins and anemones and the degradation of corals also take their toll. 4
How to recognise it
Tap a number on the photo: the key explains what to look for.
- 1Frayed first dorsal fin the tasselled tip is typical of this species 3
- 2Long second dorsal fin it has greatly elongated rays, like the anal fin 3
- 3Black and pale bars in sharp contrast on the silvery body 3
- 4Whitish dots the pattern varies from one individual to another 3
- 5Deeply forked tail deeply split into two lobes 3
Life in the wild
Where it is found
Shallow, calm water between coral reefs and seagrass beds. 3 It usually stays between 1 and 2 m; FishBase gives 16 m as a limit. 2 Also common near jetties, on silty sand bottoms with the seagrass Enhalus acoroides. 2 It depends on other organisms for shelter: the young mainly on anemones, adults on hard corals, soft corals, branching sponges and seagrass, and all ages on sea urchins. 4
Reproduction
It has separate sexes and does not change sex. It matures in less than a year, at about 4 cm standard length. 4 The female produces an average of 59 eggs per spawning (from 20 to 102), measuring about 2.5 mm. 2 4 The male holds them in his mouth until they hatch and goes on guarding the young for another 5-7 days, releasing them at 6-8 mm. There is no larval phase in the plankton. 2 4 After release the juveniles immediately look for shelter, partly to escape cannibalism. 4
In the aquarium
From the experience of the BallingMania community.
A fish belonging to the family Apogonidae, place of origin the western Pacific Ocean: it was originally limited to the areas around the island of Banggai in Indonesia, although later, thanks to human intervention, its range also extended to the Taliabu Islands and Luwuk. In the wild it lives in channels and on the outer slopes of the coral reef at depths of 10-65 m. It has an almost circular body, only slightly elongated and strongly laterally compressed; the rounded head is very large and takes up the whole front of the body; the mouth is very large; the eye, set at the tip, is very large; the gill cover is also very large; the caudal peduncle is long and thin.
The livery is silvery grey with turquoise shading; on the flank there are four vertical bands, usually black or dark brown; the first of these bands crosses the forehead and the mouth, the second the eye, while the third and fourth join the dorsal fins to the pelvic fins; except for the head, the flanks and fins are decorated with numerous bright white dots.
A gregarious fish, it lives in large schools that hunt by day in algae meadows or among the branches of coral reefs; very often they take refuge among the spines of Diadema setosum. It lives well with all species of small, peaceful fish that are not greedy when getting food. It can also be kept in tanks that are not too large, but with plenty of hiding places. It is advisable to buy a group of at least three animals, but once the pair has formed, remove the extra one from the tank, as otherwise it would be killed by the pair. The alternative is to keep large groups, in keeping with the size of the tank.
In the wild it feeds mainly on small crustaceans, fish eggs and larvae and other small components of the zooplankton. Once introduced and during acclimatisation it accepts food with difficulty, but once settled in it is carnivorous. It prefers frozen food, thawed in a little aquarium water before feeding: brine shrimp, Chironomus, Mysis; it rarely accepts freeze-dried and dry food.
It is one of the few marine fish that can be bred easily even in an aquarium. The male takes care of brooding, being ovoviviparous: he incubates the eggs in his mouth, which is also used to protect the fry after hatching; the young will leave the parent's mouth once they have reached a length of about 8 mm.
Pterapogon kauderni can be called "reef safe".
Species sheet by Massimo Ramognino and photo by Natale Ispanico Profeta
What studies say about keeping it
Data from official reports and studies, not advice for a home aquarium. A review cited by NOAA states that it breeds well in captivity and could serve as a model for rearing ornamental fish. There are breeding facilities in Ambon, Makassar, Bali and the Jakarta area, but their contribution to the Indonesian trade remains insignificant. In the United States, in 2013, arrivals of captive-bred specimens from Thailand reached about 75% of the average imports of previous years, and some shipments were mistakenly declared as wild. 4 A systemic iridovirus infection has been described in wild specimens. 10
Did you know?
Sources
- Froese R., Pauly D. (FishBase) (2026). Pterapogon kauderni Koumans, 1933. World Register of Marine Species.
- Froese R., Pauly D. (eds.) (2026). Pterapogon kauderni, Banggai cardinalfish. FishBase.
- NOAA Fisheries (2026). Banggai Cardinalfish. NOAA.
- National Marine Fisheries Service (2021). 5-Year Review: Banggai cardinalfish (Pterapogon kauderni). NOAA.
- National Marine Fisheries Service (2016). Final Listing Determinations on Proposal To List the Banggai Cardinalfish and Harrisson's Dogfish Under the Endangered Species Act (81 FR 3023). Federal Register.
- GBIF Secretariat (2026). Pterapogon kauderni, IUCN Red List category. GBIF.
- UNEP-WCMC (2026). Pterapogon kauderni: common names and CITES and EU lists. Species+.
- Hoffman E.A., Kolm N., Berglund A., Arguello J.R., Jones A.G. (2005). Genetic structure in the coral-reef-associated Banggai cardinalfish, Pterapogon kauderni. Molecular Ecology.
- Vagelli A., Burford M., Bernardi G. (2008). Fine scale dispersal in Banggai Cardinalfish, Pterapogon kauderni, a coral reef species lacking a pelagic larval phase. Marine Genomics.
- Weber E.S., Waltzek T.B., Young D.A. et al. (2009). Systemic iridovirus infection in the Banggai cardinalfish (Pterapogon kauderni Koumans 1933). Journal of Veterinary Diagnostic Investigation.
Sources checked on 4 November 2026. Community texts and ratings are kept separate from the scientific data.
