Banggai Cardinalfish


Breeding pair of Banggais



We initially purchased four banggai cardinalfish in order to obtain a pair. While the fish were being quarantined, one of the fish began chasing two of the fish into the corner. We hoped this was the sign of a pair forming, and we rescued the hiding fish. As we would learn later, these two fish would indeed be a breeding pair, and are shown in the photo above. We have observed little sexual dimorphism, with the only notable feature being the way the fish position their second dorsal fin. Males not carrying eggs tend to hold their second dorsal fin very upright, such that the angle between the fish's upper surface and the dorsal fin is nearly 90 degrees. The females tend to position their second dorsal fin in a more angled manner, such that the angle formed between the upper surface and the fin is about 70 degrees. An interesting exception is that the male positions this fin in the same manner as the females while carrying eggs.


Spawning Behavior

We have observed the spawning behavior occuring over the course of up to 36 hours. In each instance the female will pursue the male, swimming beside him and shimmying then swimming around behind him, sometimes nipping his tail, then swimming beside him on the other side. We do not know what induces the spawning behavior, but in each case the pair spawns about one week after releasing a batch of fry. This has been observed when the male is removed from the tank containing the female and reintroduced immediately after releasing the fry. If the male is quarantined for several weeks before being reintroduced to the female, they spawn approximately one week after reintroduction. We have no indication that this spawing is brought about by water changes or change of environment, since in one instance the fry were released into the main reef tank, and the pair still spawned one week after release. Identical spawning behavior has been observed in several pairs of banggai cardinals and in fry as young as two months.


First Batch

After approximately one month after receiving them, the pair spawned. Three weeks after spawning, we placed the male into a 20 H tank filled half way with water, with only a sponge filter, a heater, and two plastic plants. We set the temperature at 78 degrees F with specific gravitiy of 1.024. We lit the tank with only ambient lighting. The male held the eggs in his mouth for 25 days before releasing two fry. On day 26 he released twelve more, day 27 he released about fourteen. On day 28 the final six and we immediately returned him to the reef tank fearing he would eat the fry. He would not eat for about five hours after releasing the last fry, so the danger of him eating them immediately seems nominal. We found one dead on day 27 and one died on day 30. We had tried to seed the sponge filter in the reef tanks, but in the week or so it was in the sump it did little good, so ammonia and nitrite build up was a concern. Before he started releasing fry, we added live freshly hatched brine shrimp enriched with selcon to the 20H tank. We would continue to feed these to the fry approximately three to five times daily. Each day we would change about two gallons of the ten to twelve gallons that were in the 20H. The fry would eat the brine shrimp, but did not exhibit any type of frenzied feeding behavior. The gentle current in the tank allowed the brine shimp to remain alive, as we will explain later, we believe maintaining nearly constant food availability is the key to achieving low mortality rates.


After the fry were about three weeks old, we had lost only the first two and had thirty-four remaining. We were concerned about ammonia and nitrite build up, so we moved the fry to a 10 gal tank with live rock and a skilter 250. We put netting over the skilter intake so the fish would not get sucked in. At this point, the pair had spawned and released a second batch of fry (see below). In an effort to conserve tank space, we moved the first batch of fry into a 30 gallon tank and placed a plastic tank divider into the tank. On the side with the first batch of fry, we placed 20 pounds of live rock and a CPR Bakpak. The fish continued to grow with few additional losses.


We began feeding the these fry adult live brine, once they were eating this well, which only took a few days, we started feeding only frozen brine. They were not interested for a few days, but finally some began eating it. Those that weren't eating frozen were looking thin, so we moved them to the other side of the divider, which contained the second batch of fry (as explained below). Those that were eating frozen brine grew very quicky and we only lost three more fish. It was difficult to keep track, but we believe we lost about five before they would eat frozen food and approximately three after.


Batch Two

As mentioned above, the pair had spawned a week after releasing the first batch of fry. The second batch of fry were placed on the opposite side of the tank divider, with the first batch of fry, live rock and the CPR Bakpak on the other side of the 30 gallon tank. We had hoped that the divider would provide low current in the end with the new fry, and the live rock on the other side would alleviate the problems with ammonia and nitrite. After the fry were released, about 32 after four weeks, we feed the second batch of fry newly hatched brine shrimp and frozen selcon-enriched brine shrimp to the older fry. The younger batch would frequently exhibit almost spastic behavior during feeding, they would swim very quickly in spirals and fall to the bottom of the tank, lying on their sides or upside down. If they were gently squirted with water from a turkey baster they would swim around. If they were left lying on the bottom, they would most likely die. When the second batch reached three weeks, we had lost approximately ten, within the span of the next weekend we lost fifteen more fish to this spiraling seizure. With the tank set up this way, the Bakpak removed the baby brine shrimp from the side with the small fry quickly. This resulted in a lot of food immediately after the fish were fed, and little to no food other times. We tried to compensate by feeding less food more frequently, but the fish still ate so quickly they would start having these spasms.



Four week old Banggais


Third Batch

With the third batch of fry we realized our mistake with the second batch, and placed them into a 10 gal tank with a sponge filter and one medium (10 lb)piece of live rock. The live rock was sufficient to keep the ammonia and nitrite levels to zero. We did water changes at about twice a week and tried to maintain a constant supply of newly hatched brine shrimp. I only observed the spiraling death behavior on a couple occasions. We tried to feed this batch both live and frozen to avoid the problem of those that refuse to eat the frozen and become thin. But they wouldn't take to the frozen and therefore grew very slowly. In an effort to conserve space, we learned another unfortuate lesson. We placed the third batch of fry in with the few fish from the first and second batches that had not found permanent homes in other reef tanks. This was a 30 gal reef set up with an overflow. Although the fry were several weeks old, we were constantly rescuing them from the overflow box. The oldest fry paired off and to our dismay, banished the rest of the smallest fry to recesses in the rock. It was difficult for these fish to find food.


The oldest fry that paired off in this tank did spawn, but the male only carried the eggs for two days before releasing them. This is most likely due to his young age: only four months old.

Summary

In our experience, it seems that the key to low mortality rates in raising Banggai cardinal fry are the following:

1