The genus Julidochromis is endemic to Lake Tanganyika and is popular among aquarists, as all of its members are ideal aquarium fish. They can be bred in aquariums and exhibit interesting breeding behaviors, including cooperative breeding. Cooperative breeding occurs when fish other than the parents help raise the young. Nonbreeding group members will share responsibility in guarding Julidochromis fry, while the parents will pay relatively little attention to their brood. This interesting behavior alone is reason to set up a tank for these amazing fish, but they are also beautiful and not difficult to keep.
All Julidochromis species are specialized cave-spawners, which usually deposit their eggs on the ceiling of the shelter they use as a spawning site. That is why they have to turn upside-down when spawning. In their natural habitats, the breeding site is a horizontal rock crevice or a large flat stone, which was previously undermined by both breeding partners. In comparison to other substrate breeders, Julidochromis species lay few eggs. A clutch rarely contains more than 40 eggs, which usually have a grayish-green coloration. At a water temperature of 77 degrees Fahrenheit, the larvae hatch after approximately three days. Although they begin to move their pectoral fins and tails after hatching, they stick to the ceiling of the breeding shelter by means of adhesive glands on their napes for several days.
On approximately the 10th day after the parents spawn, the fry begin to swim along the walls and ceiling of the spawning site. But before they leave the shelter for the first time, four or five more days may pass. Having a length of about 0.12 inches, the fry are very tiny. In contrast to the fry of most other cavebrooding cichlids, they are individualists and do not form a school guided by their parents. Nevertheless, they stay together because of their close ties with the breeding site and the territory of their parents. Julidochromis fry have a furtive way of life because they always swim in close contact with the substrate and seldom dare to move into the open water. As they are effectively concealed by their camouflage, aquarists often do not notice them and are highly surprised when several weeks later, they for the first time discover fairly large juveniles swimming through the aquarium.
Cooperative Breeding and Brood-care Helpers
In contrast to other cave-spawners, the parental care of all Julidochromis species appears to be much less intense. Even when caring for eggs or larvae, breeding pairs seem to pay relatively little attention to their offspring, for both parents spend little time in the shelter. But the parents can reduce their workload without any negative consequences because they usually live in a family group and are assisted by helpers (Taborsky and Limberger, 1981; Heg and Bachar, 2005).
In all of the Lamprologini tribe, there are only 20 species that practice cooperative breeding. All Julidochromis species belong to that group of 20 different species for which cooperative breeding was described (Heg and Bachar, 2005). The other cooperative species are Neolamprologus species from the N. pulcher/brichardi species complex. Among these cichlids, the fry and smaller group members are actively guarded by larger group members, which participate in all duties of the breeding pair and thus assist the parents in raising their brood. In J. ornatus, the typical composition of such breeding groups is a large dominant breeding male and female, and up to five smaller-sized subordinate group members (Heg and Bachar, 2005). In J. marlieri such a cooperative breeding group often has about a dozen members (Taborsky and Limberger, 1981). In my large community tank (106 gallons), a breeding group of Julidochromis sp. ‘Kipili’ had seven members.
Julidochromis Breeding Timeline*
Day 3 to 4:
Eggs hatch (if kept at 77 degrees Fahrenheit)
Day 4 to 9:
Fry stick to the ceiling of the breeding shelter
Fry begin to swim inside of the shelter along the walls and ceiling
Day 14 or 15:
Fry leave the shelter for the first time
Day 21 to 25:
Fry grow quickly to about 0.8 inches
Parents begin to drive juveniles out of the territory once they reach 1.2 inches. Several juveniles may become helpers in their parents’ territory.
* This timeline is approximate. Times can vary based on a number of conditions.
These helpers show the same social and helping behavior patterns that breeders show to ensure their reproductive success and the survival of the brood. But in contrast to the breeding male and female, which in their natural habitats are present at the shelter only 48 percent of the time, the helpers usually guard the breeding shelter 94 percent of the time (Heg and Bachar, 2005). Their helping behavior includes digging at the breeding shelter, guarding, fanning and cleaning the brood, maintaining the territory and defending it against conspecific intruders, egg predators and piscivores (Taborsky, 1984).
Newly established breeding pairs, which at the beginning have no helpers, are joined by individuals from the large pool of independent fish comprising 50 to 70 percent of the total population in the lake (Awata et al., 2005). In addition, the number of helpers is later increased by offspring remaining in the family group and the territory for a prolonged time. Thus breeders that die may be replaced by the largest helpers in the group.
Most of the helpers are nonreproducing males (Heg and Bachar, 2005). These nonbreeders show submissive behavior patterns toward the breeders, which threaten them with aggression and the risk of expulsion from the group. The helpers display several appeasing signals to be accepted in the territory. In order to appease a breeder, subordinate group members fold their fins, bend the body into the shape of an S and approach the dominant fish swimming backward (tail first) and try to nestle against the dominant male’s head. These appeasing signals effectively reduce the potential for behavioral conflict in the family group (Bergmüller and Taborsky, 2005).
Care and Breeding in a Tank
Particularly the smaller Julidochromis species are ideal for aquariums. They can be kept in a tank only 1.6 feet in length, if certain conditions are met (Staeck and Linke, 1994). This, however, requires a harmonic pair. More detailed observations are possible in a tank about 5 feet long; under such conditions, several pairs can be kept with other smaller cichlids from the tribe Lamprologini (e.g., Chalinochromis, Telmatochromis or Neolamprologus species). For more than 10 years, I have kept Julidochromis ornatus, Julidochromis sp. ‘Kipili,’ Julidochromis sp. ‘Marlieri Zambia’ and Neolamprologus multifasciatus together in about 120 gallons. Although all species regularly bred and raised part of their offspring, no cross-breeding occurred.
Decorate the aquarium naturally with numerous narrow crevices between flat stones and rocks, which may serve the fish as breeding sites and shelters. Cover the bottom of the aquarium with a thick layer of sand or very fine gravel; these cichlids like to dig and to undermine stones to build shelters. Apart from algae, there are no plants in the habitats of Julidochromis, but it is possible to decorate some of the rocks in the tank with Microsorum pteropus or Anubias species.
Although a harmonic pair will successfully breed in a relatively small aquarium, good results can also be achieved in a naturally decorated community tank. Keeping Julidochromis species in small tanks may be a problem because they are sensitive to even the slightest disturbance. Breeding pairs that regularly and successfully reared their offspring in the past suddenly began to engage in vicious fights if there was any change in their aquarium. Even water changes can be the stimulus for such fights, which often result in the death of the subordinate specimen.
Supplement to Breeding Julies
As the fry of all Julidochromis species are very tiny, very small food is needed for their rearing. The nauplii of the brine shrimp Artemia salina or finely crushed flake food are good options. If kept in a community tank, there is no need to feed the young fish separately, as enough tiny food particles are left over when the adults are fed. Provided with sufficient quantities of food, the fry will reach a size of about 0.8 inches after three weeks. But afterward, they grow relatively slowly. When they have a length of approximately 1.2 inches, the parents begin to drive them out of their territory. However, even under aquarium conditions, cooperative breeding groups can often be observed because regularly one or two juveniles grow up, reach maturity and are still tolerated as helpers in the territory of their parents. All the helpers are accepted as group members, at least for a certain time. Members expelled by the dominant pair have to be taken out of the aquarium if they suffer (if the aquarium does not offer enough space). In a really large community tank (e.g., 120 gallons) with numerous hiding places, even expelled members usually survive without any problem.
If you want to see the amazing breeding techniques of these cichlids from Lake Tanganyika, pick up a group at your local fish store. As long as they have a large enough tank and are provided with a good living environment, the aquarium should be peaceful. The reproductive behaviors of the Julidochromis species are some of the most interesting that you will be able to witness in a captive environment. FAMA
Wolfgang Staeck has a Ph.D. in biology from the University of Berlin. He is a lifelong cichlid enthusiast specializing in cichlid behavior. He has published the scientific descriptions of more than a dozen new fish species and was the first to report on the behaviors of many cichlid species. He is an educator, lecturer, author, and president of the German Cichlid Association.