Breeding Banggai Cardinals

Pterapogon kauderrni

Let me state at the outset that I am no expert, nor did I intentionally set out to breed Cardinals. I simply wish to pass on my successes and failures in the hope that it might help others to achieve the eventual success that I have had. Without the assistance of keen amateur aquarists I firmly believe that the future of the Banggai Cardinal is bleak. In nature they are found in a limited area that is already under pressure and, unlike the various species of clown fishes, they are not commercially viable due to the fact they produce so few offspring per mating.

The Setup

My one hundred and twenty gallon reef tank has been up and running for some 18 months, during which period it has accumulated an eclectic display of corals, invertebrates and fish, the first of which were three adult Cardinals. Mistake number one. I was unlucky (foolish) enough to end up with two males and one female. All though the most passive and "reef friendly" of fish, when ready to mate, the males become extremely aggressive towards each other. I ended up with a pair, a female, and a very ragged male, the results of his battle to the death with the other male. In retrospect this was stupid of me, as it is fairly easy to distinguish the sexes; the males having a more pronounced and squared off jaw line. Two gallon glass tank. Small air pump, tubing and diffuser. Child's paint brush, razor blade on a stick, breeder net, small capture net. Algae - This cost me 75 dollars for one litre and 25.59 dollars carriage, import tax etc., however I now have enough algae to last me several years at the current rate of usage!

Spawning

Some weeks later I noticed the male had stopped eating. (As an aside it is worth noting that very few Cardinals will take prepared foods, so a potential owner must always have to hand frozen or live foods.) I became quite concerned, then I noticed his vastly extended jaw line and became even more so. As the days progressed I noted he became very still, seldom moving from one of the least turbulent areas in my reef. About his only movement was a curious sort of yawning motion. Then all was revealed! One morning during one of his "yawns" I noticed two tiny heads poking from his cavernous mouth. These minute fry were an exact replica of the adult in every respect, truly a wonder to behold. The day after the male was eating again and the fry had vanished. OK, so now I owed nature at least three Cardinals; time to do some serious research. Very little has been published in books, that I could find, on breeding Cardinals. Through email and the web I was able to pick up a few tips and hints - The fry are released at night and immediately seek the sanctuary of some protective object or creature from which they dart out on occasion to feed from the plankton mass. Well it was a start! Three weeks later I noticed the male had stopped eating again. Being more "clued up" this time I was able to see a clutch of large pink eggs in his mouth as the yawning had started again. I guess this is some sort of stirring action designed to keep the eggs oxygenated and free from debris. A week and a half later he was eating again, but no fry. This happened for a second time, then I think I figured it out. The male is going without food for several weeks with only a few weeks in between; the poor chap must be starving! There then followed a period of intense observation. I now know that prior to laying her eggs the female slides along the side of the male and does a sort of wriggle dance. This is my cue to start "bulk feeding" the male, not easy in a tank that contains many other, some larger, inhabitants. Here the male Cardinals biology helps a great deal. He may not be the biggest fish in the tank, but boy he has the biggest mouth! He now gets a period of several days when he is fed large chunks of squid, krill and lance fish until he can eat no more. Since starting this regime the male has not aborted a single clutch.

Fry

Protecting the fry once they were out of the adult's mouth now became the big issue. Over a period I saw them consumed by a green hammerhead coral, a plate anemone and several species of fish. I tried netting the fry, I tried siphoning them nothing worked. There were two factors working against me; the structure of my reef with its densely packed corals and the amazing power and speed of these four millimetre fry. Working on a tip received from a fellow reefer I introduced a spiny urchin to the reef. I am convinced that the male Cardinal actively seeks out the urchin when it is getting close to release time as, on three occasions now, I have found the fry swimming between the spines when the urchin has been in different locations within the tank. I have never observed this behaviour though. No I'm not lazy! On numerous occasions I have stayed up to observe the tank under dim red lighting until three and four in the morning. I have also tried getting up at 5am, but I have never seen the release. I guess this is just one of those things a chap likes to do in private! It does not help that the total time from eggs through fry to release is inconsistent. I have no idea (yet) what natural event, if any, triggers the release. The fry are very, very reluctant to leave the urchin and move with him for days at a time wherever he goes. Eventually though the fry will become a bit bolder and venture a fraction and zap, some reef inhabitant or other will get them. The knack I have discovered is to steer the urchin into a space where I can manoeuvre a net without the fear of upsetting the reef or near by corals. When the urchin is on the rear glass this is easily achieved by razor blading the glass, leaving only a green "path" in the direction you want him to go. In other locations a gentle brushing of the spines with a child's paint brush will cause him to move in the desired direction. Getting him to stop when he gets there is another matter! Once both the urchin and the fry are somewhere "safe" I introduce a small net and scoop the fry from within the spines with a high degree of success. Some times an odd spine or two gets broken off but the urchin doesn't seem to mind, they grow back in any event. Having netted a fry I transfer it to a breeder net suspended from the metal halide lights above the tank; safe at last! I did think I was being unfair to the urchin at one stage, so constructed an "urchin" out of cocktail sticks and milliputy to the correct dimensions. No way was the adult Cardinal having any of it, he completely ignored the structure in favour of the real thing every time. This dummy urchin now sits inside the breeder net to keep the fry company. They are obviously not as astute as the parent because they quite happily swim between the wooden spines.

Feeding

The final hurdle is feeding the young. This for me turned out not to be a problem as I had been conducting some experiments with a blend of cryopreserved algae, a 25 percent mix of Tet, Nanno, T-ISO, and Pavlavo strains that I imported from a company in the USA. I extracted a couple of gallons from the main reef into a small glass tank, inserted an air line with diffuser, and added brine shrimp eggs. Once the eggs hatch I drip feed this small tank with a solution of the algae. Twice a day, when the actinic tubes are on, but not the halides, I scoop up a wine glass full from the brine tank and feed it to the fry, replenishing the brine tank with a wine glass full of reef water. Every other day I add some more brine eggs and top up with RO DI water as required. This has given me a continuous supply of mixed sized brine shrimp to feed the fry, with the additional benefit of also feeding both algae and the brine small enough to escape the breeder net to my other reef inhabitants. Once the fry attain a noticeable growth, I add some frozen baby brine to the mix in order to wean them off live foods. My biggest fear is that the brine tank will "crash" leaving me with nothing to feed. To date this has only happened once, during my early experiments when I over fed algae to the brine tank causing it to stagnate. If I had started out with the intention of breeding Cardinals there is no way I would have set things up as they are now, but as I said at the beginning, the whole thing was an accident in the first place. I think I have demonstrated however that your average hobbyist with your average mixed reef set up can, and indeed should be encouraged to breed this truly magnificent reef inhabitant, from captive bred stock only though please!

By Rennie Bowe