Ctenopoma ocellatum - The Zulu Perch
By David Marshall
of the Ryedale Aquarist Society, North Yorkshire, England
Aquarticles
Endemic to the Congo River system of Zaire, Ctenopoma ocellatum is known in
the aquarium hobby as the Zulu Perch/Bushfish. As we shall see this is not a geographical
reference to one of Africa's great tribes but relates to the colour pattern of our subject
fish.
This is a very leaf -like (always reminding me of the ace of spades symbol in a
horizontal position) labyrinth fish, moulded by nature to blend into riverine debris, that
is crepuscular in habit. As with all members of the Ctenopoma genus the Zulu
Perch is nocturnal by nature and, as an ambush predator, has the ability to expand its
mouth incredibly quickly in order to snatch and swallow small prey.
Please note that catching and moving a Zulu Perch with a net is not recommended as
these particular fish are well armed with an array of spines that are present on the hind
margins of the gill cover (which is why the Manyspined Bushfish/Climbing Perch was
scientifically named Ctenopoma multispinis) and these spines can quickly cut
through fine netting thus often puncturing the aquarists' fingers (which if anything like
the wound, and resulting horrendous pain, I received from the pectoral fins of Synodontis
'species Zaire' is best avoided) in the process.
Closely related to the Asian Climbing Perch (genus Anabas) these fish also
have the ability to haul their bodies overland for short distances, in order to move from
one body of water to another. Out of interest the indigenous people(s) of Zimbabwe have
many legends and superstitions that surround the overland movement of Ctenopoma
multispinis, as their ancestors believed that this particular Bushfish (a 'tag' given
to all the Ctenopoma species due to their resemblance to floating leaves and
driftwood) fell with the rain, as it is not uncommon for specimens to be caught many
kilometres from the nearest body of water in the hours following heavy periods of
rainfall.
Thankfully, and unlike some other members of their genus, the Zulu Perch does not have
a reputation for doing death leaps from aquaria, although a tight fitting lid should be
used in order to prevent any such potential escape acts.
So how did these fish gain their common name? To answer this question look at the
foreground body colour of a mature specimen and, unless their background colour is
particularly dark, you will see an amazing cross-striped pattern that the first European
naturalists to see Ctenopoma ocellatum likened to the battle formation of locked
together diamond-shaped shields they had heard was used by Zulu warriors in Southern
Africa.
These fish require a spacious aquarium with one of 90x30x30cm the minimum size.
Remember to follow the airspace rule for labyrinth fish, leaving a space of 2.5cm between
water surface and condensation shield, as deprived of the chance to gulp at atmospheric
air the Zulu Perch are unable to maintain their labyrinth organ in full working order thus
effectively drown (many a Siamese Fighting Fish, Betta splendens, has been lost
in aquaria due to the same reason). The Zulu Perch will do well with a pH of 7.5 and a
temperature of 25 C. It is essential that they have a number of places of concealment
provided by tall plants and mopani wood etc.
The types of food they accept is never usually a problem as all commercially produced
aquarium fish foods are quickly swallowed down. What you must be careful of is the actual
amount you feed as these fish, in particular lone females, can become exceedingly greedy
taking as much food as they can cram into their mouths and this can lead to problems with
a condition similar to the cichlid disorder 'Malawi bloat'.
Although they will make an extra meal of any other fish small enough to fit into their
mouths the Zulu Perch can be kept alongside large Asian Barbs (in particular Tinfoils),
Silver Dollars, large Botia species (whose quick movements do sometimes have a
'spooking' effect on all Bushfish species) and Synodontis.
As with all Bushfish this can be a long lived aquarium fish (some members of the Ctenopoma
genus have had aquarium lives in excess of 20 years) so please give thought to this before
making a purchase as Zulu Perch (like Koi and large catfish) need to be with aquarists
with a commitment to their long term care.
Once settled in their aquaria Zulu Perch will relax their nocturnal instincts and can
become very outgoing. In lightly stocked aquaria this can cause a problem as the Zulu
Perch, in particular lone females (once again), may soon come to dominate in such a
situation and will pick out individual tank mates to nip and chase causing as much
psychological as physical damage to their victim(s).
What we know about the reproduction aspects of these fish is that, at maturity, males
often develop small spikes on some of their scales, females are more rounded in body and
that reports of spawnings in the wild speak of egg scattering activity. To date there are
no published accounts of an aquaria spawning of the Zulu Perch but with an ever increasing
number of Bushfish appearing in aquatic retail outlets, through the commercial aquarium
fish farming operations of Eastern Europe and from hobbyists in Holland, we may not have
to wait much longer for news of such an event?
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