(This article was originally published in Freshwater and Marine Aquarium Magazine, Feb 1982; pp. 30-39, 66-76. It is here reproduced with the permission of author Dr. Paul V. Loiselle).
One of the most remarkable attributes of the genus Pseudocrenilabrus is its extensive latitudinal distribution. The Egyptian Mouthbrooder occurs as far north as the Nile Delta, while the southerly distributional limits for P. philander approximate closely those for the Family Cichlidae in the Old World tropics. The genus Haplochromis must take the honors for the most northerly occurring haplochromine, for a single species, Haplochromis flaviijosephi occurs in the Jordan River system, but no other representative of this group of cichlids penetrates as far southward. The central African representative of these wide-ranging little cichlids is Pseudocrenilabrus ventralis (Nichols 1928).
This strikingly colored species was described from material collected at Ankoro, at the confluence of the Lualaba and Luvua Rivers in the southeastern portion of Zaire. Nichols originally ascribed this species to Paratilapia, a cichlid genus endemic to the island of Madagascar now known to comprise just two species, P. polleni and P blekeeri. Nevertheless, he noted affinities between his new species and P. philander and P. multicolor. Subsequent data have confirmed his perspicacity in this regard. Gosse (1963) records this species from Yangambi, in the central basin of the Congo River, but this citation aside, nothing else is known with certainty of the distributional limits of this species. It is certainly possible that some of the Pseudocrenilabrus material from farther south in the Shaba (Katanga) region of Zaire that has been referred to P. philander may in fact belong to this species. It is also reasonable to infer that P. ventralis occurs in the eastern tributaries of the Lualaba between the Luvua and Ituri rivers. However, until additional collections are made from the tremendous expanse of the Congo Basin, the exact boundaries of its range will remain unknown.
The precise date of its importation is unknown, but in the United States, P. ventralis became available as an aquarium fish in the latter part of 1970. Its dissemination in this country was in no small measure due to the activities of Tom and Nevin Bailey of San Diego, California. Through their commercial breeding operation, the Baileys sold substantial quantities of this species under the trade name of Black and Gold Mouthbrooder or Black and Gold Haplochromis. One can find no cause to quarrel with these highly descriptive designations. Less praiseworthy was the practice of other wholesalers who offered this fish for sale under the name Hemihaplochromis philander. While closely related, these two species differ dramatically in their adult coloration. This transferal of names only served to confuse aquarists as to the nature of the true P. philander. The type locality of P. ventralis lies outside of the forested zone of the Congo Basin, but this species has also been reported from the heart of the central basin in an area of true rain forest. No data is available on the ecology of this species in the Ankoro area, but Gosse (1963) has published such information for the Yangambi populations. In that forested area, P. ventralis is found in small creeks tributary to the Congo River. These habitats are characterized by fine sand bottoms, overlain in places by leafy detritus. Vascular aquatic plants are rare in such habitats. However, during the dry season, when nutrient concentrations are relatively high, blooms of filamentous blue-green algae do occur in areas where sufficient light penetration allows their growth. The stomach contents of specimens examined by Gosse suggest that P. ventralis browses over the substratum for its food. While the remains of aquatic insects predominated, diatom cases and algal filaments were also found in the stomachs examined, revealing a pattern similar to that reported by Welcomme (1969) for P. multicolor/Uganda.
This species seems to be tolerant of an exceptionally wide range of water conditions. The water in the Yangambi area is soft and quite acidic, yet P. ventralis thrives equally in the hard alkaline waters typical of the central and southwestern United States. Like all members of the genus, P. ventralis is sensitive to the build-up of nitrogenous wastes in its environment and greatly benefits from a regular program of frequent partial water changes. Remarkably enough for a species native to tropical lowland habitats, P. ventralis can withstand temperatures as low as 13°C. for short periods of time, while prolonged exposure to 16°C. appears to do it no harm. As with P. multicolor. a temperature range of 24°C. to 29°C. is more suitable for general maintenance. The behavior of this species in captivity is similar in most respects to that of P. multicolor. There is no data available on the expression of its territorial behavior in nature, and thus no way of knowing how large a territory a male will usually defend or how long he will defend it. In captivity, the usual rule is one dominant male per aquarium in tanks under 300 1 capacity, which argues fairly convincingly for the sort of social behavior in the field that we will encounter in P. philander. This behavior is rather unfortunate, as only dominant males display to its fullest extent the striking black and gold coloration that is so characteristic of this species. 5ubordinate males resemble females in their less pronounced coloration. This apparently does not elicit high levels of aggressive behavior from a dominant male. Thus, provided the tank has ample cover, it is possible to keep more than a single male per aquarium. I suspect the foregoing will have a familiar ring to keepers of Malawian Haplochromines and their relatives!
The spawning behavior of P. ventralis parallels that of the Egyptian mouthbrooder in all respects. Males display to potential mates with great vigor. Even in relatively cramped quarters, females are rarely injured during this pre-spawning play, contrary to the case in other representatives of the genus. The ova of this species are pale beige, pyriform, and measure 3.5 mm along the major axis. The total number spawned can vary from six to over a hundred, depending upon the size, age and condition of the female. A brood of 45 to 50 fry is not uncommon for a female 4.0 cm SL. Females are very good mothers and should be handled like ovigerous Haplochromis females (Loiselle, 1978). The incubation period of this species is 14 days at 25°C. As is the case with those of both the Egyptian and Ugandan Mouthbrooders, the fry of P. ventralis, which measure 6.0 mm to 7.0 mm SL at release, are slenderer and smaller mouthed than are comparably aged Haplochromis fry. They, thus, must be offered only the smallest live foods for the first week of their lives. Microworms are a highly acceptable and easily cultured choice. The growing fry tolerate neither crowding nor poor tank maintenance. Aquarists complaining of difficulty in rearing fry of this species are invariably guilty of one or both shortcomings. Overall, I found this species more easily induced to spawn and more easily reared than any of its congeners save the Egyptian Mouthbrooder. This may very well be because the fish available to me as breeding stock were third or fourth generation aquarium-reared specimens. Once given a good start, the fry of P. ventralis grow rapidly. At four weeks of age, males measure c. 1.5 cm SL and begin to develop a red spot at the distal tip of the anal fin, a feature that marks them as true Pseudocrenilabrus. With increasing age the anal fin becomes duskier, until the distal spot is overlain and completely masked by black pigment. Sexual activity can commence as early as eight weeks postrelease. Females as small as 2.0 cm SL have carried broods successfully. Regular spawning generally commences at twelve weeks postrelease, by which time males will have grown to 3.5 cm SL and females to 3.0 cm SL. Individuals of this species can attain lengths as great as 10.0 cm SL, but it is rare to encounter even in captivity specimens of either sex larger than 7.5 cm SL.
Pseudocrenilabrus ventralis is, without a doubt, one of the most beautiful and desirable haplochromines to have been introduced to aquarists over the last decade. In addition to a striking indeed a unique color pattern, this species combines ease of maintenance and general hardiness with small adult size and a gratifying willingness to spawn. It is, therefore, all the more regrettable to report its apparent disappearance from the ranks of available cichlids, at least on the American side of the Atlantic. Like many riverine Haplochromis species, it appears to have fallen victim to its own best qualities and to competition from the more glamorous and economically rewarding haplochromines of Lake Malawi. I suppose that the strong novelty component that motivates the actions of most cichlid fanciers, combined with the economic realities of maintaining a collection of fish make such "boom and bust" cycles all but unavoidable following the introduction of a newly available species. Nevertheless, this situation should still fail to reconcile any serious cichlidophile to the loss of even one cichlid species to the hobby. One can only hope for the eventual reintroduction of such "lost" cichlids under circumstances that will result in their successful establishment among the ranks of commercially available ornamental fishes.
The southerly outrider of the genus, Pseudocrenilabrus philander, was described by Weber in 1897 on the basis of material collected from eastward-flowing streams in Natal, South Africa. In 1902, Hilgendorf described a similar fish from small springs and streams in the vicinity of Otavifontein, Namibia (Southwest Africa) as Haplochromis leubber1i. Trewavas (1936) studied the collections of P. philander made by Dr. Karl Jordan in Namibia. After comparison of this material with specimens from other parts of southern Africa, she divided P. philander into three subspecies:
- P. philander philander (Weber 1897), native to eastward-flowing streams from the mouth of the Zambezi River southward to the vicinity of the city of Durban, South Africa.
- P. philander dispersus (Trewavas 1936), native to westward-flowing streams from the Orange River in South Africa northwards to the upper tributaries of the Congo River.
- P. philander luebberti, limited in its distribution to the Otavi Pan in Namibia.
The nomina Haplochromis moffati and Tilapia ovalis were considered by Boulenger (1915) to be respectively senior and junior synonyms of P. philander. Trewavas (1936, 1973) regards both to be junior synonyms of Tilapia sparmannii, the types of both nominal species being far larger than the largest recorded specimens of P. philander. Ichthyologists have generally accepted this conclusion. As is frequently the case, however, the aquaristic literature was slow in picking up taxonomic information from the scientific. Hence in most reference works published prior to 1970, this species is listed under the inaccurate designation of Haplochromis moffati. Both H. mogati and T. ovalis have been employed to designate this species commercially as well. As I indicated in the first installment of this series, Pseudocrenilabrus natalensis Fowler 1934 is a junior synonym of P. philander.
Data in Sterba (1967) suggested the biosystematics of this species to be rather more complex than Trewavas' account would suggest. This view is amply buttressed by information communicated to me by Dr. Anthony Ribbink, which he obtained during the course of his doctoral research at Rhodes University in Grahamstown, South Africa. While carrying out neuro-behavioral studies of P. philander, Ribbink was able to characterize six distinctive populations of this nominal species which differ recognizably from one another in details of coloration, certain aspects of their behavior and in the size of their ova. These populations breed true, and while they can be successfully hybridized, when offered a choice, a female will always spawn with a male of her natal population. This situation has its closest parallels among several distinctive species complexes within the genus Aphyosemion and the problems it poses to both ichthyologists and aquarists are comparable.
When my own observations are added to information provided by Ribbink, Pseudocrenilabrus philander appears to be divisible into the following subunits:
Natal and East Coastal populations, corresponding to the typical subspecies, P. philander philander;
Lake Sibaya population, endemic to a small lake in Zululand, in northeastern South Africa;
Orange River basin populations;
Wondergat population, endemic to the Wondergat, a limestone sinkhole near the city of Mafeking, not far from the border separating South Africa and Botswana;
Kuruman Eye population, endemic to a shallow limestone sink near the city of Kuruman in western South Africa;
Lake Otjikoto population. The type material of P. philander dispersus was collected from this Namibian sinkhole;
Otavi Pan populations. These populations are, of course, synonymous with the subspecies P. philander leubberti. A very strong possibility exists that every sinkhole or spring in Namibia boasts its own distinctive population of nominal P. philander, each possibly meriting specific or subspecific status, a situation analogous to that seen in the genus Cyprinodon in the southwestern United States and northern México;
Zambezi and Okavango River basin populations. Possibly these fish correspond to the "small form from Beira" discussed by Sterba (1967);
Lake Chilwa basin population;
Lake Malawi basin population;
Upper Congo River basin populations. The status of the Pseudocrenilabrus material collected from these rivers is uncertain. Trewavas (1973) assigns it to P. philander, but in view of the similarities between juveniles and young adults of this species and P. ventralis, it seems likely that additional research is required in order to determine whether a representative of the P. philander complex does indeed occur in the Congo basin and if so, to what extent, if at all, its range overlaps that of P. ventralis. Biogeographical considerations would strongly suggest that any representative of this complex occurring in the Congo basin would be very closely related to the Zambezi basin populations.
The accompanying color photographs adequately represent several of these populations. Only five of these distinctive forms have to date been imported into Europe or the United States as aquarium fish. They are:
The Natal-East Coastal form. These cichlids were exported in large numbers in the early 1970's by the South African firm Circa-Africa Ltd. Their progeny are sporadically available in both North America and Europe. This appears to be the fish marketed by several Florida breeders under the name Tilapia ovalis.
The Lake Otjikoto form, imported at least once into Germany. Sterba (1967) gives no indication of successful spawning of this fish, which appears not to have become established in the hobby.
A fish from Mozambique referred to by Sterba as "the small form from Beira" that is probably identical to the Zambezi-Okavango River basin form of P. philander. This animal was also apparently imported into Germany on a one shot basis. There is no indication it ever succeeded in becoming established as an aquarium fish or that it was ever imported into the United States.
Lake Malawi basin form, exported episodically along with Astatotilapia calliptera since the onset of commercial activity on Lake Malawi. I know of several successful spawnings of this fish, but am uncertain of its present status in North America. Contrary to the case with the other forms considered herein, the possibility of reimportation is quite high for this population of P. philander.
The Lake Chilwa basin form, first imported into the United States in the autumn of 1972. This fish may well have been widely distributed under the erroneous name of P. multicolor, a forgivable mistake as its brassy gold base coloration resembles that of the Ugandan Mouthbrooder far more than it does that of the more familiar blue color scheme of other populations of P. philander. It was bred successfully but like P. ventralis, it appears to have been lost as an aquarium fish.
I suspect that several of these distinctive forms of P. philander were lost simply because cichlid hobbyists were not aware of their unique nature. I hope now that the polytypic nature of this species is known, hobbyists will exert greater efforts to maintain viable captive populations when future importations of these fish become available.
The Pseudocrenilabrus philander superspecies comprises some of the most ecologically versatile of all haplochromines. The nominate subspecies occurs in small streams, the marginal zones of large rivers, swamps and marshes and even saline estuaries. Contrary to the usual pattern for the genus, several representatives of this complex have even succeeded in colonizing lacustrine habitats, such as Lake Sibaya and numerous sinkhole lakes throughout southern Africa. Its failure to establish itself in Lake Malawi proper may be reasonably explained by the presence of competitively superior haplochromines. Ribbink reports, not surprisingly in such an adaptable cichlid, that P. philander is quite catholic in the matter of habitat preference and appears to prosper equally over a wide range of substrata and in both planted and unplanted biotopes. This fish prefers to remain close to the substratum, rarely moving higher than one meter above the bottom. As one might expect in such an instance, it obtains most of its food from foraging through the substratum, though small swimming prey such as zooplankton are taken when the opportunity to do so arises. According to Ribbink, in shallow water, individuals will rise to the surface to seize stranded terrestrial insects such as ants or termites.
This species is tolerant of a wide range of pH and hardness values. Ribbink indicates that P. philander can survive in waters of up to 29% salinity and even reproduce successfully at salinities of 17% that of seawater. In the aquarium, neutral to slightly alkaline, moderately hard water is appreciated. Like its congeners, this species will not tolerate a build-up of nitrogenous wastes in its environment and requires a program of frequent partial water changes to do well in captivity.
With regard to temperature, South African populations of P. philander can withstand brief plunges to 12 °C and prolonged exposure to temperatures as low as 16 °C. The optimal temperature range for representatives of this complex is identical to that for P. ventralis. Male aggressiveness is heightened and the length of the incubation period is reduced at the upper end of this temperature range.
According to Ribbink, all forms of P. philander are readily maintained and easily induced to spawn in captivity. My own experience would lead me to exclude the Lake Chilwa population from such a generalization, but I certainly cannot fault its pertinence to either the Natal-East Coastal or the Malawi basin populations. Successful breeding requires that one take into account a most interesting aspect of male behavior in these cichlids, notably the tendency to defend large, relatively persistent territories in nature. Ribbink states that the size of these territories shows some variation according to the time of day, but the core area rarely measures less than a meter in diameter. Given the size of a male P. philander, this observation suggests a distinctly peppery temperament during periods of sexual activity! The practical implication of such behavior is quite clear: One territorial male per aquarium in any tank under 400 l capacity. Additional males can coexist only as non-territorial supernumeraries, a role that is not alien to them in nature. However, in the confines of an aquarium, such a situation is highly unstable and requires careful management to prevent the outbreak of serious intraspecific fighting or the loss of aterritorial males through systematic persecution by the solitary territorial individual. Problems are much less likely to occur if multiple male groups are deprived of female company, as levels of aggression are significantly lower in the absence of females.