 |
|
| Home | Marine Aquariums |
Freshwater Aquariums |
Planted Aquariums |
Brackish Systems |
Ponds,
lakes & fountains |
Turtles & Amphibians |
Aquatic Business |
Aquatic Science |
Ask the WWM Crew a Question |
| Please visit our Sponsors | ||||
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.
Fascinating
behavior 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.
Divorce--Julie
style! 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 °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. Decor
When it comes to the décor, 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, décor, 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!
References 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)) Figure captions
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
© Mary Bailey
2. The Kipili population of J.
regani, usually known as the Kipili Regani, is atypically slender for
the species. © 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.
© 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. © Neale
Monks
6. Neolamprologus brichardi is
a relatively easy to keep and readily available Tanganyikan cichlid
that mixes well with Julies. © Mary Bailey. |
|
|
Features: |
|
| Featured Sponsors: |
