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Nanochromis transvestitus by Uwe Werner
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Nanochromis transvestitus is
one of the most beautiful dwarf cichlids of West Africa. The females in
particular attract attention because of the bright red belly and their
distinctly marked black and white striped fins.
I found some Nanochromis
transvestitus, a small colorful cichlid from West Africa, in an
importer’s tanks in Dülmen (Germany). I had not previously kept
this fish but I recognized them from photographs. I did know that to
properly care for this fish, and certainly to breed it, I would need to
use soft and acidic water. Because the small size of this fish allows
it to be maintained in small aquaria, I decided to use rainwater which
I could acidify with peat extracts. This would satisfy the key
requirements for keeping this species, and also for breeding it.
Once I had my newly acquired
fish —I bought a pair—I wanted to learn as much as I could about this
species. You have to go back several years to find information on how
to care for or breed them. Often you can find only brief comments
accompanying individual photographs, but seldom can you find concrete
information. This is surprising considering that the fish was described
in 1984 (Stewart & Tyson 1984)—I am grateful to Anton Lamboj for
providing me with a copy of the original description—and they were
imported soon thereafter according to Jörg Freyhof. Freyhof was
probably the first to mention this species in the aquarium hobby, in
1986 in the DCG-info (German cichlid magazine) and in 1987 in the DATZ.
In November 1987, Hans Joachim Richter also published a breeding report
in the AT (Aquarien Terrarien Monatsschrift), the aquarium magazine of
the former German Democratic Republic, which I highly recommend if only
for the wonderful pictures. Inside, the photographs are black and
white, but check out the colorful back page.
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Origin and Ecology
The type locality of
Nanochromis
transvestitus is in Lake Mai-Ndombe— formerly called Lac Inongo or Lac
Leopold II—in the Congo River (also called the Zaire River) basin.
Tyson R. Roberts and Donald J. Stewart carried out an ichthyological
survey on the south shore of the lake in 1973. The shallow lake drains
into the Fimi River, formerly called the Lukenie, which in turn flows
into the Kasai, the largest southern tributary of the Congo. The water
of the Mai-Ndombe is black; so black in fact that you can no longer see
your hand at 20 to 30 centimeters (8 to 12 inches) depth. The water is
also very acidic. At sites where scientists found N. tansvestitus, the
pH was 4.0. The shore is composed of porous rock and everywhere
uprooted trees have fallen into the lake, probably the result of
frequent storms. The substrate, where there are no rocks, is covered in
layers of hard-packed fine sediment and rotting vegetation. Freshwater
sponges of the genus Spongilla with hard, sharp edges grow on the rocks
and trees along the shore. In the original description of the species,
the authors indicate that the most brightly colored Nanochromis
individuals were found in dark, rocky areas, where they occur in
relatively high numbers. Perhaps they form colonies and they are highly
territorial.
Richter (1987) wrote that N.
transvestitus lives in fast moving streams, close to Lake Mai-Ndombe,
in quiet waters with rocky bottoms. Possibly Richter incorrectly
translated the original description because it is clear that the
holotype—a female of 30.7 mm (1.2" ) Standard Length—and the 118
paratypes, which ranged from 16.5 to 33.8 mm (0.6 to 1.3") SL were all
captured using rotenone from the shore of Lake Mai-Ndombe between the
waterline and a depth of 1 meter (3.3 feet).
Stomach examinations revealed
that
the fish in their natural habitat eat benthic invertebrates,
particularly cladocera, midge larvae, mites, and detritus as well as
large quantities of what appeared to be pieces of sponges. The tooth
arrangement is appropriate for this kind of diet; the teeth have brown
tips, are conical and in two rows. The outer row of the upper jaw
contains 42 to 50 teeth in an adult fish, whereas younger fish have
fewer teeth. The pharyngeal teeth have a large, slightly curved primary
cusp and at least one second, smaller cusp.
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Distinguishing
characters of the genus and species
Stewart & Roberts (1984)
placed
their new species in the genus Nanochromis, which was created by
Pellegrin and literally means “colorful dwarf”. The genus is endemic to
the Congo (Zaire) basin and includes the type species N. nudiceps and
seven other nominal species. These species differ from all the other
African cichlids by having the upper lateral line contiguous with the
dorsal fin base along more than half its length. Another distinguishing
characteristic is the bone structure of the head; the absence of the
cheek and neck scales and having five sensory pores on the mandibles
and seven on the preopercle including one pore on the upper tip.
Characteristics
of the species are
The original descriptors remarked upon the reversed sexual dichromatism and therefore chose as a species name transvestitus, which means that they are of the opinion that normally in cichlids males should be more colorful than females. This view surprises me, as well as Lamboj (2004), who wrote that this form of reversed sexual dichromatism is seen in many different genera and species of chromidotilapiine cichlids and is now known to be the norm for the group. Stewart & Roberts suggest that comparative studies of the reproductive behavior of the Nanochromis might be interesting. |
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I had previously read about the
fish
and knew that they were secretive breeders, and only did so in soft,
acidic water. When I purchased my pair, I already had a small aquarium
measuring 30x25x25 centimeters (12x10x10 inches), that I had set up for
a pair of Badis badis. I added a little bit of sand on the bottom,
filled it with rainwater that I had filtered for several days using
activated charcoal and installed a sponge filter next to two homemade
clay caves with small entrances. A couple of slate tiles and a bit of
Java moss added some privacy if you even can speak about that in such a
small fish tank. As I put the fish in, I put in two alder cones and
also hung a bag with black peat in the tank to acidify the water.
Initially I kept the water temperature low, between 22 and 23 °C
(72-73°F), because the tank was located low in my fish room. From
my
experiences, I believe that Nanochromis and other related species
(Limbochromis and some Pelvicachromis) are frail at temperatures that
exceed 25°C (77°F).
Although you may hear that it
is
difficult to pair N. transvestitus, everything worked out well for me.
After just a few days of the two fish being together, the female was
colored up with a bright red belly and intensely striped fins, and she
performed her courtship display in front of the male. She contorted her
body in every imaginable manner: the base of the tail was raised, the
belly pushed downwards, or the whole body was bent sideways in an
S-shape, so that the female showed off her red abdomen to the male.
Then she confronted the male, lifted her head all the way back, opened
her mouth, and swam around the male with her mouth wide open. All this
was done in a hectic manner, with the female constantly changing her
position in a zig-zag pattern such that the male was on one side and
then the other. By now, the male also looked handsome: his body stripes
were darker and all the scales had thin dark edgings such that a fine
grid pattern emerged against the light background.
During courtship, the female
inspected the two clay caves and removed all the sand from one of them.
The pH of the water had settled down to about 5, and only one week
later the pair spawned, on a Sunday morning. The female sat in the clay
cave next to the orange eggs, which were attached to the ceiling of the
cave. Each egg was not very elongate, more roundish, and hung at one
end from a bundle of threads (a stalk) — I could not see this very well
because it was inside the tiny cave — but the eggs would swing back and
forth when the female moved inside the cave. The largest dimension of
the eggs measured about a millimeter (0.04") in my opinion, and I
estimated the number of eggs to between 50 to 60. By the way, they were
not all clustered densely together but rather were loosely distributed
over the ceiling of the cave.
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A surprising experience
I was totally surprised that
the fish
spawned so quickly and naturally it got me excited and nervous. So I
checked many times that day to see if the female was still inside the
cave. That was always the case until I got a terrible surprise that
evening: the front glass of the fish tank had cracked and a third of
the water had already drained out! What now?
I had to think quickly. I took a slightly smaller aquarium that I always have sitting around, put a little sand in it and siphoned water into it from the leaking N. transvestitus aquarium. Then I covered the entrance to the cave with my fingers—securing the female and eggs inside—and moved it to the new aquarium. Next I transferred the male and then filled the rest of the tank with rainwater, which happened to be at an acceptable temperature. The next day I found the female in the cave, caring for the eggs. I was full of joy. Two days later the eggs were gone and the female was outside the cave. I shone a light inside the cave, but did not discover any larvae on the bottom. I was disappointed! Because in the meantime I had repaired the original fish tank, I decided to move the fish back because the size of the tank fit better and also matched my other tanks. I used the same interior materials and the majority of the water. Then I moved the pair of fish. They did not seem to mind; they felt right at home here or there. Six days later I could not believe my eyes. All of a sudden I found a large school of fry at the entrance of the cave, digging eagerly in the sand accompanied by their parents. Even though they had been forced to move twice, the mother had nevertheless taken care of them. From that point on, it was no problem to raise the young. From the beginning, they ate brine shrimp nauplia and they grew rapidly. After four weeks I moved them out of the parents’ tank. First I tried to suck them up with a siphon hose, but they were already too strong and large to be captured that way. So I emptied the tank completely, and I put half the water in a nursery tank and filled it up over the next couple of days bit by bit with hard water out of the faucet (pH 7.2–7.5; 19º dGH; 11º KH). The young fish proved to be very robust and grew up without failure. The main food was newly hatched Artemia, with occasional feedings of Grindal worms and broken up food tablets. Once in a while, I fed them frozen Cyclops. When it came time to distribute them to friends in France, sometimes pairs would be in transport bags for three days, but all fish survived even this test with no failures. |
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Various
breeding methods
I filled up the tank with the
parents
with rainwater filtered through activated charcoal and peat bags. The
fish did not fight but did not spawn either and one day I found the
female dead. I did not recognize any symptoms of illness, nor injuries,
so I assumed that the male did not kill her. However, I wanted to breed
them, so I put all my hope into the young fish. After about half a
year, the young seemed to be sexually mature. I put them into three
smaller aquaria sitting side by side. I also put in small caves for
spawning. In all cases, I arbitrary formed pairs from the young fish.
Parallel to these tanks, I placed a larger aquarium of 50x25x30 cm
(20x10x12") with sandy substrate, and densely planted with Cryptocorn
and Anubias. It had slate stone as a decorative background. A large
Ceratopteris provided subdued light from above. The tank was already
filled with rainwater and had some rummy-nose tetras, armored catfish
from Suriname, and a few young Ancistrus catfish. I hoped, nonetheless,
that a pair would spawn in this aquarium because I had hoped to
photograph or perhaps even film them in that environment.
In the three smaller tanks the
pairs
got along well, but not in the large one. In that tank, the male was
not accepted by the larger female, at least not yet. But because there
were plenty of hiding places, I hoped that the male would put on weight
with good food and that they would get together eventually. I was
planning on introducing a black peat bag at the appropriate time to
condition the water.
By the way, I did not feed them a lot, which you might have expected. Almost everyday they had live brine shrimp, that they eagerly enjoyed, but only every 3 or 4 days I gave them a couple of Grindal worms and once in a while small Daphnia and Cyclops from my garden pond. Between those were white fly larvae, which they seemed to especially like. Also occasionally I gave them half a feeding tablet, which was intended for the 3 or 4 young Ancistrus that I put in every tank to clean up the leftover food. |
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Success
and failure
For more than four weeks
nothing
happened, then I saw the females in the small fish tanks performing
courtship displays. I checked the pH level and found out that because
of the length of use of black peat it was 5, 5.5, and 6.5. In the
following weeks, all three of the pairs spawned! Because I could see
well into two of the caves, I realized that in each cave they had about
50 to 60 eggs. Four days later, as I came home from work in the
afternoon, I found the hatched larvae. The majority of them were
hanging on the cave ceiling and cave walls. Some were lying on the
bottom of the cave. Because the female only stayed inside the cave for
the first two days, it was easy to observe the development of the young
with the help of a flashlight, without interrupting the brood care. In
the fish tanks with a lower pH, the eggs and larvae developed without
any problems, compared to the other ones in which clearly fewer larvae
hatched and some died after hatching. The female collected the dead
eggs, formed them into a ball and moved it outside, where I sucked it
up with a thin siphon hose.
After hatching, it took about 8
days
till the young fish left the cave for the first time. In the tanks with
lower pH, I counted about 50, whereas in the other tank only 13 young
survived. Probably the reason for the long development time was the low
water temperature of the tanks. Freyhof (1987) had mentioned that at 24
º to 27 º C (75 to 81 ºF) the larva hatched on the third
day, and were
free swimming after four more days.
Meanwhile, the pair of fish in
the
larger tank, with a lot of thick plants in it, also spawned;
unfortunately I realized it too late. The parents had dug a large cave
next to the spawning cave which was obviously completely clean. In the
other tanks, the fish had less opportunity to dig, because of the small
amount of sand. As I put my peat bag in the large tank, it was
evidently too late. All the hatchlings died and again I found them
three days later as a fungus ball in front of the cave.
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Brood
Care
Two weeks later the fish
spawned
again and the water values were now correct. Apparently all the eggs
developed and the parents did not loose any young to the tetras or
armoured catfish. The catfish in particular were under a lot of
pressure and hid behind the rocks so the adult Nanochromis did not
notice them.
In my impression, the male plays a larger role in the care of the young while they were free swimming. When I showed up with a camera, the male courageously remained by his young, while on the other hand, the female would disappear. The female preferred to hang out in dark, protected places with her young. In order to shoot some photographs, the only opportunity was when they were close to the front of the tank. So most of the time I was only able to take one or two photographs. I also had the impression that the female was less colorful when looking after her young, compared to her courtship colors. This makes sense: she is not supposed to be as conspicuous at this time. The first couple of nights after free swimming, the mother stayed with the babies in the cave. Later on, the young slept outside and often each parent cared for a group of the young, in doing so, they sometimes were apart from each other. The previous authors reported that N. tranvestitus is not overly quarrelsome, compared to other species of Nanochromis, but the pairs repeatedly had fights, for example before the female laid the eggs in the process of mating (Richter, Freyhof) and also at the time of brood care they would bite each other (Freyhof), so sometimes they needed to be separated. I also observed aggression towards the female when the young were free swimming. Her reaction was to resort to her courting colors—she quickly showed her pretty red belly and apparently that pleased the male. |
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References
Freyhof, J. (1986) Nanochromis transvestitus—ein Zaire-Cichlide im Sträflingskleid. DCG-Info 17(9): 163-166. Freyhof, J. (1987) Ein Außergewöhnlicher Zwergcichlide aus dem Lac Mai-ndombe, Zaire. DATZ 40: 156 -158. Lamboj, A. (2004) Die Cichliden des westlichen Afrikas. Bornheim. Linke, H. & W. Staeck (1981) Afrikanische Cichliden I: Buntbarsche aus Westafrika. Melle, Germany. Richter, H.-J. (1987) Nanochromis transvestitus Stuart & Roberts, 1984 ein schöner neuer Zwergcichlide aus Zaire. Aquarien-Terrarien 34(11): 368-370. Stewart, D. J. & R.R. Tyson (1984) A new species of dwarf cichlid fish with reversed sexual dimochratism from lac Mai-ndombe, Zaire. Copeia 1984: 82-86. |
