Article by Frank C. Marini Ph.D., Copyright 1996. Reproduced by permission.
(This article first appeared in Volume 4 Issue 4, The Journal of MaquaCulture 1996.)

Fig. 1 Adult female Pterapogon kauderni.
Notice the rounded body compared to fig.2

INTRODUCTION: The Banggai cardinalfish (BC) Pterapogon kauderni (a.k.a. the banner cardinal, black and silver high fin cardinal, and/or outhouse cardinal), is an attractively patterned black and silver cardinalfish. This species was initially collected and described by Gerald Allen in September 1995 [1], and is primarily found in the mid waters off the remote Banggai island in the Indonesian archipelago. His initial observations were that these fish aggregated in small groups of 2 to 60 animals living among the spines of sea urchins. Allen has proposed that they are nocturnal feeders eating primarily planktonic crustaceans. Like most cardinalfish they have large eyes and reside in the crevices and beneath rock ledges by day, searching the bottom for food at night [2]. While BC attain a length of 2 to 2-1/2 inches Standard Length (SL), most specimens encountered in the tropical fish stores are 1 to 1 1/2″SL[3].

A unique feature of these cardinal fish is their manner of mouth brooding reproduction. Typically cardinalfish incubate their eggs orally until they hatch, at which point the fry swim away and enter the water column. The BC is different in that the male shelters the young for the first weeks post hatching. Observed in the mouth of one BC male were 26 juveniles measuring up to 11 mm in length [1].

Fig. 2 Adult male Pterapogon kauderni.
Notice head/jaw and long banner on second dorsal fin.

According to Michael [3], the BC is a hardy aquarium resident, and should not be aggressive toward other tank residents. In his article, Scott Michael expresses concern, however, with the sudden popularity of this fish: because of its limited population range and unique breeding behavior, these fish could be seriously over collected and wild populations decimated.The following article describes my experiences with acquiring, raising, and breeding the BC. From this point on, I would like this report to be a narrative.

ACQUIRING THE ANIMALS: I saw my first BC at a local Houston pet store in Jan. 1996. I had never seen a cardinalfish so beautiful and purchased it for $100. For the next week it was a great tank (footnote 1), until I added another BC. Hours later the first BC proceeded to shred the fins off its new brethren. I quickly removed this fish and returned it to the store, exchanging it for another larger BC. Fortunately this new animals was well received. For the next 5 months I fed the fish four times weekly with “enriched” brine (footnote 2) and “gut loaded” ghost (footnote 3). The BC are very easy to care for and very tolerant of my water and temperature conditions.

THE MATING DANCE: I noticed in early July that one of the BC was chasing the other around. After a few hours (this activity started in late afternoon and proceeded into the night) it began circling the other fish. When one reached the others eyes it would shimmy, then swim in front of this fish and shimmy on the other side. Later, the other fish responded by “dancing” around the back side of the other: it would lightly nip at the (left rear) back side, then immediately swim behind and nip at the other side (right rear). This was repeated until the lights went out in the tank (9:30 PM). The following morning, one fish refused ghost shrimp (their favorite food). I realized then that this “dance” I witnessed could possibly be a mating ritual. Knowing that the male cardinalfish carries the eggs, and that one fish refused food, I was able to discern the sexes of my two fish. On first observation these fish do not appear outwardly sexually dimorphic. However my long term observations suggest that adult males have a larger, longer “banner” fin (second dorsal fin), which extends past the tip of the caudal fin (tail fin). Additionally, males have a different body shape than the larger, round-bodied females(fig.1). The males have a more V-like front end, with a slightly thicker lower jaw and a squatty body(fig. 2). These observations may also explain why my second BC was terrorized, it was probably another male, while the third BC was a female.

I have noticed that after breeding, the pair became very aggressive towards the other tank mates. At first the male would drive other fish away from the female, but after the male was carrying eggs the female was very aggressive about driving away the others. He continually refused food for the next 2 weeks, though I did notice that he would “yawn” often and shift this red packet in his mouth. I theorize that this “juggling” or shifting of the eggs in his mouth may allow new water to enter while removing waste. After 18 days, I observed little eyes peering out of the male’s mouth. Every time he yawned, the babies would poke out and immediate jump back in. At this time, I set up a breeder net in the aquarium, and corralled the male into it. On day 23 (23 days after refusing food) he “spit out” 5 fry in the morning and by that evening there were 15. Over the next two days he “spit out” the remaining fry-31 total. I immediately removed him from the breeder net.

THE FRY: The fry of the BC are quite large, about the size of an adult brine shrimp in length(1/4″)(fig.3). Their coloration is black and clear(see thru) stripes, no white spotting, but otherwise perfect copies of the adults. They were able to eat

Fig. 3 “Herd” of baby cardinal fish.

immediately after release, and I fed them newly hatched, “supplemented” artemia (footnote 4) (baby brine shrimp) by releasing large amount of baby brine into the net. There were definitely more aggressive eaters in the group, that would nip at their siblings, forcing them away from the food. They were constantly hungry, so I fed them 3 times daily: in the morning when the lights came on (8:15AM), right after work (5:30 PM) and right before the lights went out (9:30PM). The fry displayed a tight “herding” response (most likely a protective mechanism), with the group constantly shifting together. Whenever I would peer into the net they (the “herd”) would immediately dart into the plastic plant. During the lighted hours they schooled near the plastic plant never venturing far from it. At night they hugged the plant and turned sideways, perpendicular to the plant stem appearing from the top as leaves of the plant. At feeding time they all came out to eat at once.

I had no problems with the fry for the first 10 days. After that a few died, probably from not getting enough food, for there were visibly larger fry in the group. At two weeks, my rotifer collection had finally matured, and I alternated feeding with rotifers and baby brine shrimp. I noticed that the larger fry were “bullying” some of the other fry, so I purchased another breeder net and placed 5 larger fry in this net. At the 30 day point, I had lost many of the fry, and at two months had 10 remaining. The surviving fry would not eat any “nonliving” food. They sampled flake but promptly spit it out, they tasted bloodworms, also quickly dispensing of it–they were not interested in nonliving food. At 2 1/2 months, they were capable of eating full-sized, “enriched” brine shrimp and continue to due so today.

CONTINUED SUCCESS: Fifteen days after the initial incubation the pair bred again. The incubation time and delivery were roughly the same as the first time, 22 days incubation, 28 baby fry. This time I separated the fry into groups of 5 in each breeder net, and fed the individual groups large amounts of either newly hatched brine, rotifers or both. In the following weeks I visually recorded the growth of the differentially-fed groups. After 30 days, I noted that more juveniles had survived (20 fry remaining at day 30) than the first time. The groups fed supplemented baby brine were visually larger than any of the other groups. Luckily, I

Fig. 4 Two month old juvenile, approximately 3/4 to 1 inch SL

found the brine nauplii to be the easiest to raise and feed. At the 60 day point I had 13 babies remaining and all were eating adult brine. Approximately 18 days after the second incubation and delivery, the pair bred yet again. However this time the male carried the eggs for only 5 days before spitting them out. My theory as to the reason for the miscarriage was since the pair was breeding so often, and since the male refuses to eat while carrying eggs, he was too hungry to carry them for many more days. To fatten him up I fed him twice daily, giving large amounts of adult brine and ghost shrimp. The pair bred again in early OCT, approximately 15 days after their last attempt. The incubation was routine, and I corralled the male into the net. This time he released the babies in two large batches but promptly ate many of them, leaving 17 out of 28. I guess I didn’t fatten him up enough? (I have no hypothesis as to why he ate the fry). These fry are still quite small (fig.4), about 2 months old, but are starting to eat adult brine. I have kept 4 from the first batch(4 months 2 weeks old), 8 from the second batch (3 months 1 weeks old) and 10 from the most recent batch (1 months 3 week old). While they appear to get along fine with their aged-matched siblings, I have recently separated them into 3 smaller tanks. The pair has not bred again since OCT. 28. It has been suggested that they are seasonal breeders which may be the reason.

I do not know what initiated the breedings (i.e. water changes, sunlight hitting tank) nor do I know how to prevent the male from prematurely releasing the eggs (others have suggested that leaving that male undisturbed until the fry are visible may prevent this)

SUMMARY: The Banggai cardinalfish are an excellent addition to the reef tank. They are hardy, undemanding fish, which prefer live food (although a pet store owner mentioned to me that his BC will eat flake food, and blood worms).

The male harbors the fry in his mouth for 21-24 days, then spits them out in small groups. The fry can eat immediately after release and travel in a protective school. Feed them often, with supplemented newly hatched brine shrimp nauplii, or greenwater-fed rotifers. I have found that separating the fry into small groups prevents the sibling aggression over food, however there have been reports of raising the young collectively in a larger tank. The fry require large amounts of living food and at 2 1/2 months can start eating adult brine, and at 4 months small ghost shrimp. As an important note: It was mentioned in Scott Michael’s article [3] that the BC are not aggressive, but I have to disagree. My experience is that once a pair is established, they are very intolerant of their own kind. They will drive away (and even kill) any other BC in the tank. I have tried repeatedly to introduce other BC pairs into the same tank, with the initial pair “shredding” the new fish.

Altogether the BC are excellent fish for the saltwater hobbyist. Its ability to be captive bred due to its mouth brooding reproductive method (holding the fry until they are larger, thereby facilitating the chances of the young to take larger food) may allow enough captive bred fish to be produced, to possibly alleviate the demand on wild populations. Added in proof: Since my initial posting in AOL’s marine fish section and REC.AQUARIA.MARINE in August 1996, there have been other posted reports of successful breeding of the BC. T. JAY of Mount Desert Island(email-frogglet@aol.com), Robert Goldsmith (rjga@aol.com). Also check Jeff Phofl’s web page(under cardinalfish) for more up-to-date information.

Authors Notes:

A -My Tank Setup: I have a 65 gallon long Oceanic reef ready tank, with VHO lighting(330 watts-actinic daylight bulbs). 45lbs of rock. Salinity 1.021, pH. 8.2, Ammonia(NH4-N) 0 , Nitrite(NO2-N) 0, Nitrate(NO3-N) <5.0 mg/L. SeaTest multikit. Water changes 10% bimonthly with is R.O. water/Coralife salt. Additives: Theil Liquid Gold, Boyd’s Vita-Chem, Seachems Reef calcium, Marine buffer, and Saltwater Solution’s Soft Coral growth stimulator. Tank Mates: 1-Sailfin tang, 1-ash blenny, 1-watchman goby. Temp range: 72oF lowest to 85oF+ (summer temperature in Houston, TX)

B -Enriched Brine Shrimp- I purchase two Oz of live brine weekly. I place 1 oz/gallon in individual milk jugs and fed with O.S.I. Artemia food(algae meal, wheat flour, vitamins) and American Marine’s SELCON food booster(1 ml/gallon). I add two drops Vita-Chem to brine before feeding

C -“Gut loaded” ghost shrimp- I purchase 100 ghost shrimp/every two weeks and raise in a 5 gallon aquarium. I feed with Nutrafin Staple flake fish food and blood worms. The shrimp are fed for at least three days before they are fed to the BC. I feed 2-3 shrimp/fish at each feeding.

D -Enriched Baby Brine shrimp nauplii- I hatch baby brine using O.S.I. eggs in used tank water. I keep three gallons of baby brine going at all times. Sprinkle 1 oz. eggs/gallon and add high aeration, hatching occurs in 24-48 hrs. After hatching feed O.S.I. Micro food (yeast, wheat extract, biostablized vitamins), and SELCON, plus 1 drop/gallon Vita-Chem.

ACKNOWLEDGEMENTS: I would like to thank Dr. Christine Newell and David Cutbirth (photos) for the helpful discussions and critical review. Also Edward Nash (Chicago Aquarium Society) and Bob Goldstein for the helpful information exchange.

About the Author: Frank Marini was born and raised near Boston Mass. He completed his Ph.D. in molecular biology at U.T. Houston, and is currently working on Gene Therapy cures for cancer. He has been a reef aficionado for 8 years, and besides keeping saltwater fish, raises and breeds old world chameleons(sp. Chameleo).

REFERENCES:

1. Allen, G.R., and R.C. Steene., Notes on the behavior of the Indonesian Cardinalfish(Apogonidae) Pteragon Kauderni koumans. , Revue Francaise d’ Aquariologie. 22: p. 7-9,1995.
2. Fenner, R., A diversity of Aquatic Life: Cardinalfish, Family Apogonidae. SeaScope(Aquarium Systems). 13: p. 3,1996.
3. Michael, S., The Banggai Cardinalfish. Aquarium Fish Magazine. 8(8): p. 86-87,1996 .