Ctenopoma ocellatum - The Zulu Perch, by David Marshall

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?