In the last couple of decades, the Banggai cardinalfish (Pterapogon kauderni) has become a piscine rock star! At the time it made its way into the ornamental fish trade, this attractive fish was only known from one location – an island named Banggai off the coast of eastern Sulawesi (Indonesia). Now the Banggai cardinalfish has been introduced to other locations around the island of Sulawesi, and their populations are growing so rapidly that they are referred to by divers as finned rats! What made the Banggai cardinalfish so attractive to aquarists were its bold coloration, as well as its very unusual reproductive behavior. Since the first specimens showed up in aquarium stores (at much higher prices than we pay now), it has become a common cardinalfish in the fish trade. Unfortunately, in the past decade the Banggai cardinalfish’s reputation has suffered because many wild caught specimens fare poorly in captivity.
Difficulty: Captive-raised Banggai cardinalfish often do very well in the home aquarium, while wild-caught specimens are unreliable and often die within weeks or months. Captive-raised Pterapogon kauderni will ingest most aquarium foods. Feed this fish finely chopped seafood, frozen preparations for carnivores, mysid shrimp and fish eggs at least once a day.
Physical description: The color of the Banggai cardinalfish is unique, being grayish-silver overall with white-trimmed black stripes on the head and body. There is also a scattering of white spots on the body and fins. The caudal fin is lyrelike, and the second dorsal and pelvic fins are very large. There is no cardinalfish that looks like it. The Banggai cardinalfish reaches a length of 2.5 inches.
Range: Pterapogon kauderni is found around certain islands in Indonesia. It resides on shallow fringing reefs and lagoon seagrass meadows. Pterapogon kauderni is regularly found living among the spines of the long-spine sea urchins (Diadema). The Banggai cardinalfish also lives within the tentacles of large sea anemones, such as leathery sea anemones (Heteractis crispa), long-tentacled sea anemone (Macrodactyla doorensis) and even large carpet anemones (Stichodactyla spp.). With some anemones, the Banggai cardinalfish can even contact the stinging tentacles with no apparent ill-effects. The Banggai cardinalfish is typically found at depths of less than 20 feet.
Compatibility: The Banggai cardinalfish is not aggressive toward other fish species, but it is not always that nice to members of its own kind. While it may live in a large group in the wild, if kept in small groups in an aquarium, adults will often “pair up” and begin beating up their conspecific tankmates. If the aquarium is large enough, subordinate Pterapogon kauderni may be able to avoid the bully pair. While the Banggai cardinalfish may ignore other fish species, it is sometimes picked on by more bellicose types, such as dottybacks, larger damsels, pygmy angelfish, more aggressive wrasses and triggerfish. All of these aggression issues are exacerbated if space is limited.
Aquarium conditions: The Banggai cardinalfish can be kept in nano-reefs to the largest reef aquarium. Pterapogon kauderni is not as highly dependent on crevices like many other cardinalfish. Banggai cardinalfish prefer an appropriate sea anemone (as listed above) or some long-spine urchins. (They will even adopt faux sea urchins as a refuge.) Acceptable water parameters for the Banggai cardinalfish aquarium would be: pH of 8.1 to 8.4, specific gravity of 1.019 to 1.025 and a water temperature of 77 to 84 degrees Fahrenheit.
Care considerations: The health of wild-caught Banggai cardinalfish has been suspect for some time now. Avoid an individual Banggai cardinalfish if it exhibits redness at the base of the fins, that is constantly respiring heavily and that has stringy white feces. A Banggai cardinalfish with these symptoms will often die an early death. You can treat these problems with drugs, such as Praziquantel and Fenbendazole, but this is not always effective.
Breeding: The Banggai cardinalfish exhibits a very unique reproductive mode. Not only does the male orally incubate the eggs, he also broods the newly hatched young. The male Banggai cardinalfish takes the female’s egg mass in his mouth, which consist of an average of 45 eggs (the eggs are large, measuring a diameter of around 3 mm). The female Banggai cardinalfish sometimes gets very aggressive after passing her eggs to her mate. She will not only chase other fish in the aquarium, she sometimes even attacks her egg-incubating mate! The Banggai cardinalfish eggs are held for about 20 days. The young Banggai cardinalfish are then held in the mouth for six to 10 days, and spawning can occur as often as every 25 days.