Julidochromis

Julidochromis is a genus of cichlids in the subfamily Pseudocrenilabrinae and belong to the family Cichlidae. They originate from Lake Tanganyika in Eastern Africa. This genus contains six formally described species, some of which have a number of local variants that are still of unclear taxanomic status. Further taxanomic research is needed to determine how many other species there are; they are closely related to Chalinochromis with two species sometimes appearing within this genus and perhaps that is correct. Hybridization makes attempts to investigate relationships with molecular phylogenetic methods difficult.

These are relatively small to medium in size (about 7 to 15 centimeters) and have a yellowish background color with black longitudinal stripes or a checkerboard pattern.

Systematics

The connections and systematics of the Julidochromis are difficult to solve with certainty. Chalinochromis is essentially a similar genus except for some minor modifications for eating sponges. In their mtDNA, the Chalinochromis are more related to Julidochromis dickfeldi, Julidochromis ornatus and Julidochromis transcriptus – certainly with the last two – than to any other living fish species; while Julidochromis marlieri and Julidochromis regani are more closely related to Telmatochromis. Perhaps the Julidochromis genus should be split in two, whereby Chalinochromis is linked to one line. In addition, there have been successful hybridizations between a few species of Julidochromis males and Chalinochromis females (males generally do not pass on mtDNA to their young), with the young becoming closer to the Telmatochromis. Another possibility is that Julidochromis is monophyletic and should contain Chalinochromis; in this scenario males of the predecessors of the Julidochromis marlieri and Julidochromis regani hybridized with females of the predecessor of the Telmatochromis. The Julidochromis are poorly studied scientifically and species may still exist that have yet to be described.

Ecology and Reproduction

Julidochromis species are biparental substrate breeders that reproduce in secret. They retreat into holes, cracks and crevices between the rocks. Pairs are mainly monogamous, although the largest males sometimes maintain a harem and the largest females sometimes mate with several males at different nesting sites. This has been recorded both in the wild and in the aquarium.

When a pair is broken up, the larger fish will drive the smaller one out of the territory, sometimes killing them in the process. In some species in this genus, such as Julidochromis marlieri, for example, the females are substantially larger than the males and a female Julidochromis can often dominate a male larger than herself.

Julidochromis species have two mating rhythms. Sometimes they lay a large number of eggs (up to a few hundred) every four to six weeks. Other times they lay eggs sequentially, laying a small number of eggs every few days. Sequential spawning results in nests with young of different ages living in the same nest.

They prefer to lay their eggs in caves or other cracks and crevices. After spawning, both parents care for the eggs by keeping them clean of algae and by fanning the eggs to provide them with enough oxygen. Most of the parental care is done by the smallest fish in the flock, but this may depend on the size difference within the flock.

A pair of breeding fish must protect their nest from other cichlids trying to eat their offspring. Known invaders in the lake are Tropheus, Simochromis and Petrochromis.

Julidochromis in the aquarium

Julidochromis are small dwarf cichlids that are easy to grow and care for as long as you meet their basic requirements. Like all Tanganyika cichlids, they are best kept in hard water with a pH of 8.5 to 9 and a hardness of 12 to 14 kH. Keep them in an aquarium of at least 60 – 80 liters. Also keep only one Julidochromis species in an aquarium as they hybridize easily. As described above, they can also hybridize with Chalinochromis and Telmatochromis, so it is better to avoid these species in the same aquarium.

The aquarium should be decorated with rocks to create caves and passageways for protection; like many Rift Valley cichlids they tend to be territorial and somewhat aggressive. However, in the aquarium, Julidochromis can be a bit shy and using other fish as a distraction can lessen their tendency to hide. Nevertheless, like many Tanganyika cichlids, they can be a bit aggressive. Therefore, do not keep them together with tropical fish other than cichlids.

As mentioned above, Julidochromis are monogamous species, but pairs can break up and the resulting animosities can result in the death of one of the pair, usually the smallest of the pair. If a couple splits up in an aquarium, it is better to separate the pair. Young can stay with the parents and should be fed a high protein diet such as freshly hatched brine shrimp. Sometimes they can be seen when the parents guide their young through the aquarium.

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