Boulengerochromis microlepsis in the breeding tank. Photo by Roger Persson.
(This article was originally published in "The Cichlids Yearbook 4" Cichlid Press; pp. 22-23. It is here reproduced with the permission of author Kjell Fohrman).
Boulengerochromis microlepis is, with a maximum adult length of about 70 cm, one of the biggest (maybe even the biggest) cichlids in the world. It is a notorious predator which catches its prey by pursuit. There are a few reports about its breeding technique in its natural environment but these are somewhat contradictory. Brichard (1989) and Coulter (1991) report that B. microlepis dig large craters before they spawn. Others, Kuwamura (1986) and Konings (1992) state that the eggs are laid on a flat stone, a group of small stones, or shells. When, after a few days, the eggs have hatched the larvae are transferred to a small depression, usually an abandoned nest of, for example, Cyathopharynx furcifer.
One quite remarkable feature of Boulengerochromis microlepis is the large number of eggs produced: 5,000-10,000 per spawn. In 1956 Poll investigated a number of adult fishes and found that in sexually active individuals the intestinal tract was resorbed. He drew the conclusion that B. microlepis breeds only once in a lifetime. Wang Kuo-Jung, who has bred B. microlepis in a large concrete basin, has come to the same conclusion. However, when he took the eggs away shortly after spawning the female spawned again. In a period of one month the female then laid three batches of eggs.
In captivity Boulengerochromis microlepis has been bred in basins or very large vats but I am not aware of any reports of its breeding in an aquarium. Now two hobbyist-breeders in Eskilstuna, Sweden, Rasmus Plomin and Kenneth Bengtsson, have succeeded for the first time and the following report is based on an interview with them.
In summer 1991 they purchased eight 6-8 cm juveniles from a pet-shop. These were wild caught, collected in Zambia. These 8 fishes were placed in an 250 litre aquarium in which they grew very quickly. After 8-9 months, when they had grown to a size of about 15 cm, they started to quarrel among themselves and in a short time five of them were killed. The remaining three were transferred to an aquarium with a capacity of about 500 litres in which some Malawi cichlids were housed. This proved to be much better because they stopped fighting among each other. However, they could be quite boisterous towards other fishes and easily dominated the other inhabitants.
At the time of purchase the juvenile B. microlepis were golden yellow with a blue sheen, but after 9 months the colour had changed to greyyellow with silvery spots. They continued to grow rapidly in their new home and after about another 6 months they started to fight again. This was remedied by moving them to a tank of 850 litres capacity.
By spring 1993 they had grown to a size of about 30 cm and were showing signs of pair formation. These three remaining fishes turned out to be two males and one female, with the female smaller than the males. The colour had again changed: the belly was golden yellow but the remainder of the body was ash-grey. The silvery spots were still present but much less conspicuous than before. The other inhabitants were removed from the tank, with the exception of a female Aristochromis christyi and a female Labeotropheus fuelleborni which were kept as "target fishes".
The two fishes that had formed a pair became very aggressive towards the "spare" male and during one fight he was so badly hurt that he became blind. The female began to dig a crater and tried to get the male interested in spawning, but he didn't seem interested. Time passed and the fishes grew, on a diet of shrimps and pellets, to a size of 45 cm in the male and about 40 cm in the female.
The male now exhibited a much more attractive colour golden yellow all over with distinctly marked silvery spots and blue spots on the gill-cover and cheeks: a beautiful hefty chap! The ground colour of the female was also golden yellow, but with black pigment producing more of a tiger-pattern. This pattern became more pronounced with the approach of breeding. Before spawning for the first time the female stopped feeding and began to dig a large crater with a diameter of about 40 cm down to the glass bottom. A week after the female had stopped feeding (18th Nov. 1993) the pair spawned. Unfortunately spawning took place very early in the morning (this was also the case in subsequent spawnings) so that pre-spawning behaviour was not witnessed. From the female's behaviour a few days before spawning it was obvious that she is the initiator and coaxes the male into spawning.
Tiny Boulengerochromis microlepsis fry in the aquarium. Photo by Roger Persson.
During spawning the male stays 20-30 cm above the site while the female deposits the eggs, in almost straight lines. After the female has laid a few rows the male descends to the nest, fertilises them, and resumes his position 20-30 cm above the nest. This is repeated until all the eggs have been laid.
The first spawn consisted of about 400 eggs which were guarded by both female and male. They didn't seem to bother the target fishes, but the other male was molested as soon as he went anywhere near the nest. Two days after spawning 75% of the eggs disappeared and on the third day all were gone. A day later the female began to eat again.
The second spawning took place on 13th Dec. 1993. Again the female stopped feeding a week before spawning. This time the eggs were laid not in the crater but on a roofing tile. The spawn consisted of about 700 eggs which hatched after three days. The larvae, which had a length of about 3 mm, were transferred to a small pit beneath the tile, not in the crater. They were guarded very aggressively by both parents. On the fourth day the larvae were siphoned out of the breeding tank and transferred to a 300 litre growing-on aquarium. During the removal of the larvae the parents were furious and bit both hands and hose. On the fifth day post-spawning the larvae became free-swimming and were fed newly hatched Artemia and small Cyclops. From the seventh day on the fry began to die off rapidly, probably because of the lack of food: they were too small to feed on Artemia and Cyclops. They were then fed frozen red plankton and this stopped the die-off. At the time of writing (22nd Jan. 1994) about 50-75 juveniles have survived to about 20 mm long and are growing rapidly. The day after the larvae were removed from the breeding tank the female resumed feeding.
The third spawning took place on 13th Jan. 1994. This time the female deposited her eggs in the crater she had dug before. The spawning behaviour seemed similar to that described above. This time about 1000 eggs were laid on the bottom glass. However they disappeared two days after spawning, possibly because they were not fertilised by the male.
In conclusion, we can repeat that in general the pair B. microlepis behaved rather peacefully, especially if they were too large to be swallowed, but the single male was attacked relentlessly: he had to stay behind the filter all the time. Even during the guarding of the eggs the 15 cm L. fuelleborni and 20 cm A. christyi females were allowed to swim freely around the tank. Water chemistry does not seem to be very important. The water in the breeding tank had a pH of about 8 and 50% was changed every week.