P.Kauderni pair. Male on the right.
At the beginning of 2000, the Banggai cardinal was listed as endangered species probably because of fishing for aquarium use , for this reason I decided to try to breed this oral incubator, also because of its capability to mate in captivity. However, after a year, the male wasn’t able to complete an incubation, also after a reduction of NO3 and PO4 in the broodstock tank and also after an addition of the food ratio for the pair. So I decided to proceed with the artificial incubation. The practice, I’m going to describe is particularly stressful for the adult fish , so it should not be the norm, even better I recommend to use it at least only sometimes.
COLLECTING THE EGGS
Eggs Mass
The removal of eggs can be done either at the beginning of incubation , either in the middle or at the end of incubation. The advantage in taking the eggs early is that the male will have more time to regain the fat reserves for the next spawn. Instead, the advantage of a late removal is a higher rate of survival of the eggs, in fact these are very delicate , especially during the first 10 days post spawn. The first problem is to capture the incubating father in a reef tank: the male is too elusive when lights are on, but he comes out of his burrow at dusk or at night. So during the dark period, the lights suddenly must be turned on, in this way the male remains dazzled for few minutes and he can be captured . Usually when he feels himself threatened, he spits independently the lump of eggs, otherwise we have to gently open his mouth. Once the eggs are conquered, the male could be released in the darkness.
THE ARTIFICIAL INCUBATOR
Artificial Incubator
The eggs of Pterapogon kauderni are extremely delicate: a small variation of any of the chemical value of the water decreases the hatching percentage. The incubator can be constructed by cutting a bottleneck. The piece will be turned upside down and the protrusion of the cap will be eliminated in order to have a smooth surface with no sharp edges . The open top will be covered with a filter sock. Inside the container, there is a tube connected to a pump and this pipe must get to the bottom. The water flow must be gentle, to stir the eggs without making them spin, then the water will come out from the grid at the top. The incubator composed can be hung in the main tank for maximum stability, but it must be clean weekly, or it can be inserted into a container with the same salinity and the same temperature of the tank. The container should be covered to limit evaporation and placed in the dark to avoid the growth of algae , in this way , for the duration of the incubation the container must not be manipulated.
DEVELOPMENT OF EGGS
Little fish just hatched
At this point you just have to wait for the hatching and follow the embryology of these fish . In fact in the early days, eggs are white to yellowish, then they will be more and more orange. Around the tenth day eyes will grow and the larvae continue to feed the enormous yolk sac, covering it with pulsating blood vessels. At 22-25th day, Pterapogon hatch, so the tails begin to move frantically, but the larvae are still at the mercy of the current. At this point they develop the black vertical stripes and the dorsal and pectoral fins . After 25-30 days post spawn, the small fishes are able to swim freely and begin to eat brine shrimp nauplii.
Little fishes. 10 days post hatch.
naturacaptiva 