NEWS103
5
Male
Spathodusmarlieri
with thenuchal hump typical ofmalesof this species.
Photo:Hans J.Mayland /Aqualog
bars on the posterior third of the body are
broader than the dark bars. In typical
T.
irsacae
precisely the reverse is true, ie the
darkbarsarebroader than the light.
Dwarf cichlids
All the species of Tanganyika Clowns
remain below the 10-cmmark, and only
male Spathodus marlieri approach it.
Essentially, the males of all species are
somewhat larger than the females.Inmany
color forms that is the onlyway to tell the
sexes apart. Eretmodus grow to around 8,
femalesonly6cm long;thesameapplies to
Spathoduserythrodon
,
S.marlieri
attains10/
8cm long,and
Tanganicodus
is thesmallest
of all the Tanganyika Clowns with a
maximumof 6.5 /5.5cm.
Shore-hoppers
As has already been mentioned at the
beginning,Tanganyika Clowns aremarked
shallow-water-dwellers.
But
Lake
Tanganyikanothing likeanartificial lake in
European latitudes. By contrast it is a vast
freshwater inlandseawithwaves tomatch.
Even in calm weather there is always a
slight swell, but during stormsmeter-high
wavesmaydevelop.
Tanganyika Clowns find their food –
Aufwuchs – among the rocks of the shore
region.Thisbiocover includes algaeandall
thesmall andmicroscopicorganisms living
in it. At the same time each species of
Tanganyika Clown is somewhat differently
specialized to itsclose relativesbyvirtueof
its special tooth form. Thus up to three
species of Clowns may occur together
without being in direct competition with
oneanother.
In all Clowns the swimbladder is reduced,
as too much buoyancy would do more
harm than good in their biotope. The
resulting hopping mode of swimming,
comical tohumaneyes,togetherwith their
broad lips,oftencoloredastrikingblue,has
led to their popular name. But this
shouldn’t disguise the fact that all Clowns
are exceptionally territorial fishes that can
be very aggressive, especially towards
conspecifics. In particular, males of
Eretmodus
sp.“CyanostictusNorth”often lacks theblue spottingof the southern species.
Spathodus marlieri
can develop into real
tyrants in the aquarium. Hence, despite
their small size, the aquarium for
TanganyikaClownsshouldnotbetoosmall
andprovidecopioushiding-places.
Biparentalmouthbrooders
Inaddition to theirattractiveappearance, it
isaboveall theirveryspecial formofbrood
care that makes Tanganyika Clowns so
appealing toaquarists.Specifically,theyare
biparental
mouthbrooders
with
a
permanent pair bond.Thewordbiparental
signifies that bothparents takepart in the
brood care. This is extremely unusual in
mouthbrooding cichlids from the African
Rift Lakes. Normally they are non-pairing
maternal mouthbrooders.Thismeans that
after spawning males have no pair bond
with females,who look after the eggs and
sometimes thebroodalone.
The spawning behavior of Tanganyika
Clowns will be illustrated here using
Eretmodus
asanexample.Itbeginswiththe
female using her mouth to clean the
spawning substrate–as a ruleahorizontal
piece of rock, in the absence of which the
bottomglass is often cleared of substrate.
The male swims to the pre-cleaned site,
apparentlydeposits sperm there,and then
leavesagain.
