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The members of the genus Julidochromis, popularly known as 'Julies', were among the first Lake Tanganyika cichlids to be seen in the aquarium hobby. They enjoyed instant popularity and remain firm favorites to the present day, but they also remain problematical both to keep and breed, and a challenge even for the experienced cichlid keeper.
Species and distribution
There are five described species of Julidochromis--J. ornatus, J. transcriptus, J. dickfeldi, J. marlieri, and J. regani, and J. regani itself includes two described subspecies, J. regani regani and J. regani affinis. In addition there is an undescribed form known as Julidochromis sp. 'Gombi', which may be a sixth species or a geographical variant of marlieri. All Julies are endemic to Lake Tanganyika in East Africa, and are found primarily in rocky or part-rocky habitats. Of the five species, marlieri, regani, ornatus, and transcriptus are found in suitable habitat all around the lake, but all four have a fragmented distribution, in other words, there are big gaps where they don't occur. By contrast, 'Gombi' and dickfeldi occur along only a single short stretch of coastline apiece, in the former case between two marlieri populations, supporting the hypothesis that it is just a local form of that species.
Unusually for cichlids, Julie taxonomy has to date been stable--all five species were originally described as Julidochromis, and none has any synonyms. However, that may not remain the case in future. Most of the taxonomic work was done when little was known about the wealth of cichlids the lake contains. The two subspecies of regani were described because those two forms happened to have been collected at the time. We now know that there is considerable geographical variation in most Tanganyika cichlid species, and the Julies are no exception. The reality is that there is variation between the populations at practically every section of coastline they inhabit. Sometimes the differences are minor, but sometimes they are sufficient to beg the question of whether they are the same species. However, many variants are adjacent with intermediate forms where they meet, so a large increase in the number of species seems unlikely.
Tanganyikan expert Ad Konings has put forward a rather different view. He has observed that J. regani and J. marlieri occupy different habitats (J. regani where rocks meet sand or where there is a lot of sediment on the rocks, J. marlieri purely rocky habitat with little or no sediment), likewise J. ornatus and J. transcriptus. In addition there is no known location where the two members of each pair are found together. He therefore surmises that J. marlieri and J. regani may be a single species, likewise J. ornatus and J. transcriptus, with the differences in coloration being adaptations (camouflage) to the different habitats. That would leave us with perhaps as few as three species.
Only a detailed study of all the different forms can resolve the problem, so in the meantime aquarists should avoid mixing geographical variants of what may or may not be the same species. In any case it is desirable to retain all the variants in as natural a form as possible rather than creating aquarium 'mish-mashes'.
Another problem is that the genus falls into three groups--one containing Julidochromis regani, J. marlieri, and J. 'Gombi', one with J. ornatus and J. transcriptus, and the third with J. dickfeldi all by itself as it is intermediate (in size and pattern) between the other two groups. We do not at present know if these groups are sufficiently distinct to be regarded as separate genera.
One of the main attractions of Julies is their behavior. They can be quite secretive and rarely stray far from their rocky habitat, both in the wild and in the aquarium. Often all you will see is a nose and an eye peering cautiously from a cranny. But if you sit quietly the fish will slowly and circumspectly emerge and move across the rocks with its belly towards the nearest surface, no matter what the orientation of the rock face. Thus you will see Julies swim vertically up--and down--a vertical surface, or upside-down beneath an overhang. And because they typically occupy narrow caves with no room to turn around they can also swim in reverse. What other fish can swim backwards and upside-down simultaneously?
The reason for their caution is that they are not fast swimmers and are also fairly low down in the food chain, ie potential prey for larger fishes and other predators. Their coloration is also protection in the wild, camouflage that merges into the mottled algae-coated rocks of the natural habitat.
Other aspects of their behavior can be less attractive and are the reason they remain a challenge for the aquarist. Fundamentally, although they rarely come to blows with non-Julies, they have a tendency to murder one another at the least provocation. You will rarely see any conflict, it is generally done by quiet assassination, and the first you know is when you find the body of the victim or realize it is missing. More of this below. Suffice it to say here that it is unwise to try and keep more than one pair of one Julie species in any aquarium.
Obtaining a pair
Adult Julies are easy to sex. The genital papilla of the male is usually permanently visible, the only problem being that the underside of the fish is usually close to a rock and the vent invisible. But this characteristic does mean a pair can be obtained by buying adults. The other option is to grow a group of youngsters on until a pair forms. Which course you follow may depend on what is available.
Putting two unpaired adults together is a recipe for disaster even if they 'know' each other from the dealer's tank, as a new home with lots of caves will result in both fishes trying to carve out a territory. Even a mated pair are liable to fall out. Hence an adult pair should be separated by a clear divider for a week or so while each establishes its own territory. The same applies if you move them subsequently.
Buying youngsters usually results in a compatible pair with no need for a divider. But once a pair forms--often long before they are fully adult--then they will usually proceed to eliminate the rest of the group, one at a time. You will probably not realize this is happening until it is too late. It is unwise to try and remove the 'spares' as the disturbance will like as not break the newly-formed pair bond and you may end up with just one fish if t is best simply to accept that 'natural selection' is taking place in your aquarium just as it does in the wild. This may in fact help maintain healthier captive stocks than is so often the case where every individual, no matter how weakly, is allowed to grow up and breed.
The main problem with keeping a pair of Julies is, as already hinted, the fragility of the pair bond. Any disturbance by the aquarist is liable to cause an upset, though the presence of other fishes, and any disturbance they cause, seems unimportant. And if the pair bond ruptures, the usual result is conflict and the death of the weaker specimen. In J. marlieri, J. regani, and J. sp. 'Gombi' this is usually the male, who remains smaller in these species, while in J. ornatus and J. transcriptus the female is smaller and usually ends up dead after divorce. For some reason J. dickfeldi doesn't seem as prone to domestic strife.
We don't know if murderous divorce is also the case in the wild or simply an aquarium phenomenon, but I personally am inclined to think the latter, though the reasons for the aquarium behavior are unclear. Nature is a dangerous place and killing your partner just because of disturbance is not a good trait for survival of the species. Possibly the answer is that in the wild the weaker partner isn't trapped by four glass walls. And, of course, with the exception of the occasional SCUBA diver or fish collector, no humans poking around and interfering. Even so, it is not usual for cichlids to react so badly to aquarium tinkering--many will eat their eggs or fry if disturbed by their owner, but they don't fall out and kill each other!
The likelihood of divorce must govern every aquarist activity, from tank maintenance to removing young Julies for further rearing and sale. Always think before doing anything that might cause upset, and do everything in such a way as to minimize disturbance. Plan the aquarium (and its occupants) carefully in advance, so no alterations are required later on. Never alter decor, add or remove fishes, or tinker with in-tank equipment. When changing water, siphon off as far from the pair as possible, and siphon new water in (via airline for minimal water movement), again well away from the pair.
One useful trick is to exploit the fact that most cichlids are totally inactive when it's dark. It is possible to sneak with a torch in when tank and room lights have been off for some time and quietly remove a filter for cleaning without them noticing, and replace it in similar fashion. The pair will then be tucked away in their cave and won't notice.
If it's any consolation, feeding seems to be a Julie-acceptable activity!
Aquarium and tankmates
The size of an aquarium for Julies will depend on which species is to be kept--remember, one pair of one species per tank is the rule. A pair of one of the smaller species can be kept in a 24-inch tank, while 30 inches is the minimum for J. regani, J. marlieri, and J. 'Gombi'. Generally speaking those tank sizes apply to a species tank, though where there is no competition for habitat it may be possible to have tankmates. I have successfully kept J. 'Gombi' with the mud-tunnel/shell dweller Lamprologus signatus in a 30-inch tank with a pile of rocks at one end and with sand and shells at the other, and it worked very well. Others have successfully kept a small group of Cyprichromis or Paracyprichromis in the open water above a pair of Julies.
If they are to be kept with other rock dwellers then a significantly larger tank is required, ideally with a separate pile of rocks per species, with open sand or gravel in between, to create discrete territories without constant argument. Otherwise the strongest pair of rock-dwellers may take over more than their share.
'Other rock-dwellers' covers a multitude of species and not all (by far) are suitable tankmates for Julies. Tropheus and Petrochromis are far too large and boisterous. Many a Julie has disappeared down the throat of a Cyphotilapia frontosa. Even among the smaller, substrate-spawning species there are problem areas. Chalinochromis are rather Julie-like in appearance and this may cause mutual antagonism. The smaller Telmatochromis may be hounded as they too are similar but less 'robust' in build and behavior. As a general rule of thumb, go for species that are about the same size but quite different in appearance, such as Neolamprologus leleupi and the N. brichardi group.
Julies (and Tanganyikans in general) are best not kept with fishes from other waters, and most definitely not with Malawi cichlids, a mistake still made far too often. The differences in behavior and temperament, not to mention size, will mean Julies that cower in rocky crevices and starve away.
Water and filtration
Water chemistry and quality are very important when maintaining any Julidochromis (and most Tanganyikans), they are very intolerant (ie likely to die) of unsuitable water conditions. The correct water is critical for long-term good health and any chance of breeding.
The water should be hard (in my experience the level of hardness is not particularly important but that in the wild is about 16-18 dGH), basic (ideally pH 8+), well oxygenated, totally free of ammonia and nitrite, and with as low a nitrate level as possible (< 15 ppm). The temperature should be in the range 25-27 Â°C. Too low or too high a temperature may lead to slow deterioration in health and eventual death. An acid pH is a rapid killer.
The aquarium should have an efficient biological filter to prevent ammonia and nitrite levels rising above zero, with regular partial water changes to keep nitrate as low as possible. Nitrate-rich mains water should be purified before use, for example using reverse osmosis.
Several criteria are relevant when choosing a filter. Firstly, biological efficiency is not a function solely of turnover rate. The tank will have a low population of small fishes producing small amounts of waste, and a small, low-turnover filter will be sufficient to both process wastes and oxygenate the water. The resulting low current will suit the slow-swimming Julies, but if subjected to turbulence they will probably stay unseen deep in the shelter of their caves and maybe starve.
In my experience air-powered undergravel (UG) or internal sponge filters are generally adequate for the job in hand. If a power filter is used it should be fitted so as to avoid strong currents near the rockwork, and the inlet should have a fry-excluder, as Julie fry, like their parents, are not strong swimmers. They may also be sucked into the gravel by over-vigorous UG filtration. In some ways an external power filter is preferable to the perhaps initially more obvious internal. Fry-proofing is easier, and you can clean the filter media without disturbing the Julies. For the same reasons I prefer UG to sponges, and it's always worked very well for me even though nowadays it is regarded as old-fashioned and out-of-date.
When it comes to the dÃ©cor, the primary consideration is rockwork. Julies do not dig (or at least not noticeably) and rarely venture away from their rocky habitat, so the substrate is of little or no relevance, though if tankmates have special substrate requirements those must be taken into account, of course. For example, shell dwellers usually require fine sand. Otherwise the substrate is there to cover the bottom glass (or as the UG filter bed) and to support the rockwork. It can also contain calciferous material such as coral sand to act as a pH buffer--a very good idea for such pH-critical fishes.
On the other hand, the rockwork should satisfy various criteria. In the wild rocks provide Julies with shelter from predators, breeding caves, and feeding substrates. They prefer tiny holes and crevices into which they can fit--without being followed and attacked by larger fishes. The ceiling or wall of a crevice is used as a spawning site, and the exposed, outside surfaces of the rocks are covered in Aufwuchs (algae) that harbor the small organisms on which Julies feed, picking them from the biocover.
The aquarium rockwork should likewise contain numerous crevices--if Julies have safe hiding-places they will feel secure and more inclined to show themselves. The type of rock is important--the ever-popular tufa (a very porous limestone) is lightweight and good for building lofty rocky structures, but has a surface like sandpaper and is totally unsuitable as a spawning substrate. Substrate spawners kept with all-tufa rockwork tend not to breed. Hence it is better to use smoother rocks--eg normal limestone, sandstone, slate, granite,--for at least part of the decor, or put pieces of slate into tufa crevices to provide suitable surfaces for spawning.
It doesn't matter if, in time, algae coat the rocks. This is very natural and may help wild fishes feel more at home. It will also look less stark than bare rocks--you won't find scrubbed-clean stones and rocks in any river, lake, or pool. On the other hand wood and plants are out of place, though you can include them if you feel you must, with the proviso that wood must be well-weathered and not release any tannins to acidify the water. I prefer not to risk it!
Diet and feeding behaviour
The natural diet of Julies is small aquatic invertebrates, and this should be simulated in captivity with foods such as live Daphnia, Cyclops, mosquito larvae, bloodworm, Artemia, and whiteworm. Frozen live foods are also very good and even wild fishes catch on quickly to their edibility. Tank-breds will usually take frozen immediately. Don't use live Tubifex because of the risk of disease, but frozen should be safe.
'Unnatural' foods are usually also taken once the fishes are settled in and are accustomed to the idea that what you put in is edible. Finely chopped shrimp, prawn, and earthworm are enjoyed. Small amounts of dried foods can be given, but these protein-rich, roughage-poor foods are not ideal as they don't accord with the continuous slow food intake in the wild.
Because Julies are reluctant to stray far from their rocks there is a risk of uneaten 'dead' food, as they will eat only what comes near, and won't sally forth to chase food. Live foods will, of course, eventually come into range. The uneaten food problem can be solved by having more out-going tankmates, but then the Julies may go short. Careful observation may be required to devise a feeding regime and diet that fits the particular circumstances in any given set-up.
Breeding and rearing
If you seriously want to breed Julies then a species tank is almost essential as otherwise straying fry will be picked off by tankmates. I should perhaps add that Julies will also pick off the straying fry of tankmates!
Even with ideal conditions (water, dÃ©cor, privacy, diet) Julies are often reluctant to spawn. The only answer is to provide optimal conditions, avoid any disturbance, and be patient. Once a pair does start to spawn, however, they will usually do so regularly as long as nothing triggers a 'divorce'.
Interestingly Julies have two alternative spawning strategies: batch spawning (similar to most substrate-spawning cichlids), where the female lays up to 150 eggs every 4-6 weeks; and trickle spawning, where a few eggs are laid every few days. Because they are so secretive there may be no indication that breeding is afoot (or a-fin!) until tiny Julies are seen peering out of crevices or swimming along the rocks--belly towards the nearest surface, just like adults. Presumably they find sufficient small particles or natural micro-organisms to see them through the early stage before they start to emerge.
The fry should be fed on small live foods such as Artemia nauplii, microworm, Cyclops, and Bosmina until they start to take the food offered to the adults. Here too it is beneficial not to have tankmates polishing off these live delicacies before the fry find them, and make sure you allow for the adult Julies taking a share--feed lots, in other words.
The young are usually tolerated by the adults until they reach a size of 1-1.25', but are then seen as potential competitors and likely to be hunted and eliminated. In the wild, of course, they simply swim away from the parental territory and find tiny crevices of their own. But, assuming we want to rear the fry and sell them (and they are a very saleable commodity), in captivity we have to try and remove them without causing the parents to divorce.
One method exploits the fact that when the young approach 'leaving home' size they are more inclined to wander, as well as being--like many young animals--less cautious than their parents. Typically they will leave the rocks to feed instead of waiting for the food to reach the rocks. If the aquarium has a single rock pile at one end, and the rest is open space, they can be enticed with food to the open end and a few captured then with a single sweep of the net. Choose a moment when the adults aren't watching! Don't be tempted to try for a second catch as the adults will probably have felt the water movement caused by the first sweep and be peering from the rockwork to see what caused it.
Another option is to (again!) operate by night. Again this requires the sort of lay-out described above. By now at least some of the larger youngsters will probably have left/been ousted from the rocks and be sleeping close to the substrate at the other end of the tank, especially if you feed them there just before lights out. Again, one quick sweep of the net per night is safest.
Is it worth it?!
By now you may have come to the conclusion that all this is far too much hassle. But Julie-keeping really does also offer rewards--it is immensely satisfying to keep and breed these challenging little fishes. And much more interesting than just having a 'nice' tank to look at, at least if you are a hands-on sort of aquarist.
Julies are undeniably attractive and fascinating, and they can also be frustrating and hard work. But you will never have cause to accuse them of being boring!
Brichard, P. 1989 Cichlids and all other fishes of Lake Tanganyika. TFH Publications, Neptune City, NJ, USA. 544 pp.
Konings, A. 1998 Tanganyika Cichlids in their Natural Habitat. Cichlid Press, El Paso, Texas, USA. 272 pp. (Available from www.cichlidpress.com (USA & Canada) or www.cichlidpress.co.uk (UK))
1. Julidochromis sp. 'Gombi' is the only known Julie with no longitudinal bands, just vertical stripes. It may be a geographical form of J. marlieri which has lost its longitudinal bands for some unknown reason. Photo Â© Mary Bailey
2. The Kipili population of J. regani, usually known as the Kipili Regani, is atypically slender for the species. Â© Mary Bailey.
3. This variant of J. regani exhibits the color pattern of the nominate subspecies and may be that form. Seen here in a quite unsuitable aquarium with entirely tufa rock and too many tankmates, including some inappropriate species. Â© Mary Bailey.
4. This geographical form of J. transcriptus is one of the paler variants - some others have far heavier longitudinal banding with a lot more vertical barring creating a checkered pattern. © Mary Bailey.
5. J. ornatus is one of the more widely traded Julies, and much appreciated for its bright colours, modest size, and generally good behaviour. Â© Neale Monks
6. Neolamprologus brichardi is a relatively easy to keep and readily available Tanganyikan cichlid that mixes well with Julies. © Mary Bailey.