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African Dwarf Cichlids, the Lake Tanganyikan Species: Part Two

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Paul V. Loiselle, 2004

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在這篇文章中被論述的魚種: Lepidiolamprologus meeli

(This article was originally published in Freshwater and Marine Aquarium Magazine, Jul 1982; pp. 15-19, 77-87. It is here reproduced with the permission of author Dr. Paul V. Loiselle).
Neolamprologus meeli
A young pair of Neolamprologus meeli, male above, female below, investigating an empty mystery snail shell. First of the shell-dwelling dwarfs to be bred in the United States, this species has been mistakenly sold as Lamprologus ornatipinnis, a very different fish. Photo by Paul V. Loiselle.

Part Two

All of the dwarf cichlids to date considered in this series have been substratum-spawners. While there are nouthbrooding cichlids small enough to be included in this category on morphological grounds, notably the genera Pseudocrenilabrus and Labidochromis, their behavior dictates the use of larger aquaria to ensure their successful maintenance than are required by true dwarf cichlids (Loiselle, 1979; 1980; 1982). The sole exceptions to this general pattern are the goby cichlids of Lake Tanganyika. All of these fishes are advanced mouthbrooders whose size and maintenance requirements clearly qualify them as dwarf cichlids.

The goby cichlids are presently classified in three genera, which differ primarily in details of buccal dentition and jaw architecture.

The goby cichlids are presently classified in three genera, which differ primarily in details of buccal dentition and jaw architecture. In Eretmodus, the mouth is broad and quite straight. The jaws are equipped with two to three rows of long-stalked, distinctly chisel-shaped teeth. In Spathodus, the mouth is more rounded when viewed from above. The jaw teeth are long and somewhat curved, with blunt tips. They are present as a single row in each jaw. In the third genus, Tanganicodus, the shape of the jaws and of their associated dentition are strikingly similar to those of the Malawian genus Labidochromis. The mouth appears quite pointed when viewed from above, in contrast to the case in the preceding two genera. The buccal teeth, present as a single row in each jaw, are somewhat incurved and quite pointed. As in Labidochromis, they increase dramatically in length from back to front. These similarities reflect convergance towards greater efficiency in exploiting an identical food source rather than any close relationship.

In a recent paper, Dr. Karel Liem (1979) has demonstrated that all three genera share a suite of complex skeletal and neuromuscular adaptations for selectively picking food from the substrata over which they occur. The implication of this discovery is that these cichlids comprise what is known as a monophyletic group, an assemblage of animals sharing a recent common evolutionary origin. Such a conclusion is based upon the reasonable inference that such extreme specializations have, in all probability, only arisen once in the history of the Tanganyikan cichlid radiation. Adherents of the cladistic philosophy of classifying organisms would argue from this that all goby cichlids should be considered members of a single genus, for which the oldest available name is Eretmodus Boulenger 1895. When one adds to the features identified by Liem the specializations in color pattern, egg morphology, and behavior shared by these cichlids, the dental differences upon which the three genera are based seem rather less compelling as arguments for their maintenance. While not formally of the cladistic persuasion, I do believe that in this instance, the cladists have the right idea. However, the most recent treatment of the Tanganyikan cichlids (Brichard, 1978) continues the trigeneric scheme of classifying the goby cichlids. Hence, aquarists are most likely to be familiar with them under these names. Further, no consensus has emerged among icthyologists on the merits of synonymizing the genera in question. Therefore, I will continue to utilize the trigeneric schemes herein. Table 1 lists the known species of Tanganyikan goby cichlids.

THE GOBY CICHLIDS OF LAKE TANGANYIKA

  • Eretmodus cyanostictus Boulenger 1898. (1)
  • Spathodus erythrodon Boulenger 1901.
  • Spathodus marlieri Poll 1950.
  • Tanganicodus irsacae Poll 1950.

(1) It appears that this name is being applied to two different fish. The southern, or Zambian form, is characterized by biparental mouthbrooding, while the northern, or Burundian form is a maternal mouthbrooder. The type material of Eretmodus cyanostictus was collected at Kinyamkolo, in the southern part of the Lake.

These little cichlids are characteristic inhabitants of the shallow littoral. According to Brichard (1978), the goby cichlids are never found in water over three meters deep and are most common in water less than a meter in depth. They are found over rocky rubble in areas of strong wave action. Indeed, the morphology and color pattern of the goby cichlids comprises extremely efficient responses to problems raised by life in the surge zone. The droll hopping motion of these fish is due to the absence of a functional swim bladder. Under other conditions, this would seem a liability rather than an asset. In the shallows of Lake Tanganyika, however, a small bottom-living cichlid runs greater risk of being slammed against obstacles by violent wave action than of being snapped up by a larger fish. Thus the positive buoyancy provided by a functional swim bladder is a real disadvantage to a fish living in such a habitat, for it reduces necessary locomotor control. The loss of a functional swim bladder thus represents a most important adaptation to life in a challenging environment. The powerful, ventrally situated pectoral fins and the low, heavily spined vertical fins also assist these cichlids in holding position in the face of strong water movement.

The security that the goby cichlids enjoy from the attentions of Lake Tanganyika's impressive array of piscivorous fishes is unlikely to extend to fish-eating birds. The shallow water in which these fishes live would facilitate their depredations. A cryptic color pattern is the usual response to such a threat. The coloration that endears these fish to aquarists may seem conspicuous when seen from the side in the undisturbed water of a home aquarium. When viewed from above in an environment where wave action breaks up and distorts incident light, the same pattern of dark bars and iridescent dorsal spots simply vanishes into the background. In their natural surroundings, the goby cichlids are among the most cryptic of Tanganyikan fishes to a viewer standing on the shore.

Though superbly adapted to life in the surge zone, none of these cichlids insists on a comparable environment in captivity. Strong water movement is relished but not required. Proper management of the nitrogen cycle in their quarters is, however, a non-negotiable demand. So is plenty of cover, particularly if one's object is to condomicile several pairs. While their response to conspecifics does display graded intensity, with Spathodus marlieri the most, and Tanganicodus irsacae the least intolerant of such companions, none of these cichlids could really be described as a social animal. Field observations (Berglund, 1978) suggest these fish live in pairs in nature, sharing a common home range. Conspecifics are not tolerated therein, but other goby cichlid species do not appear to evoke strong aggressive responses. This is not always so in captivity, where housing two or more goby cichlid taxa together should best be regarded as an experiment of uncertain outcome rather than normal management practice.

Eretmodus cyanostictus
A female Eretmodus cyanostictus. Males tend to be slightly larger, with a tendency towards frontal gibbosity. Both sexes display the same color pattern. Photo by Paul V. Loiselle.

Tanganicodus irsacae
A young male Tanganicodus irsacae. Note the finer mouth structure, reminiscent of that found in the ecologically analogous genera Julidochromis and Labidochromis. Photo by Paul V. Loiselle.

Neolamprologus ocellatus
Site defense by a female Neolamprologus ocellatus. All shell-dwelling Neolamprologus defend an individual shelter against conspecifics. None to date imported has as large a chip on its figurative shoulder as does Neolamprologus brevis which will attack its keeper's hand with the same vigor this individual displays in its disagreement with a female Gymnogeophagus rhabdotus. Photo by Paul V. Loiselle.

Neolamprologus ocellatus
A female Neolamprologus ocellatus excavating a "patio" in front of her shelter. if the substratum in their tanks is fine enough, most of these little fish will bury their shells, then dig a pit at their entrance. Coarser grades of gravel seem to inhibit this activity. Photo by Paul V. Loiselle.

Neolamprologus ocellatus
A female Neolamprologus ocellatus, a species which has bred many times in Europe but which to date has not been frustrated in their efforts by a paucity of males in shipments from the lake. Photo by Paul V. Loiselle.

Neolamprologus ocellatus
A male Neolamprologus ocellatus, a species morphologically similar to Neolamprologus brevis but which differs considerably from that species in teh degree of emmancipation it manifests from its shelter. Photo by Paul V. Loiselle.

Neolamprologus brevis
A female Neolamprologus brevis. Note the shorter ventrals and less pronounced soft dorsal and anal fins. females of this species also lack the tendency towards frontal gibbosity shown by males. This species has bred succesfully in the U.S. Photo by Paul V. Loiselle.

Lamprologus ornatipinnis
A female Lamprologus ornatipinnis, a species which bears little resemblance to Neolamprologus meeli, a species with which it was formerly confused. This individual came in as a "contaminant" in a shipment of Neolamprologus ocellatus. the reimportation in quantity of this most attractively patterned of the dwarf shell dwellers is hoped for. Photo by Paul V. Loiselle.

Lamprologus ornatipinnis
This attractive little fish was imported and sold as Lamprologus ornatipinnis, to which it does seem closely related. It bears a strong resemblance to Neolamprologus signatus. This photo of a male fails to show a strinkingly diagnostic feature of its color pattern. In both sexes, a large patch covers the top of the head between the eyes.There are no reports to date of succesful spawning of this species. Photo by Paul V. Loiselle.

Neolamprologus 'magarae'
A young male of an apparently undescribed dwarf Neolamprologus sold under the trade name of "Neolamprologus magarae" . Older males develop an emarginate caudal fin with white distal filaments reminiscent of those of the popular Neolamprologus brichardi. Females attain only half the size of males and lack their filamentous caudals. This species spawns freely in captivity. Photo by Paul V. Loiselle.

A certain amount of caution is also advisable when selecting other companions for these fish. Goby cichlids seem to elicit strong aggression from some other Tanganyikan cichlids. I was very surprised when the male of a pair of Lamprologus savoryi spent a substantial part of each day keeping two goby cichlids cornered in a pile of rock rubble for as long as they shared the same tank. The same goby cichlids came in for a disproportionate amount of chasing from a male Callochromis pleurospilus whenever one of his females came into breeding condition. At other times, the parties to these interactions ignored one another. Why such behavior occurred is something of a mystery to me, as according to Brichard (1978), these cichlids should never encounter one another in nature. The mutual intolerance of goby cichlids and Julidochromis species mentioned by Crout (1974) is more comprehensible. Habitat overlap between them is possible in nature, while their similar feeding patterns would put them into competition for the same resources. If their tank is liberally furnished with cover, goby cichlids run very little risk of injury from aggressive tankmates. However, such an arrangement hardly allows their keeper much opportunity to see them up and about. It is also behaviorally stressful to its victims in the bargain. My own preference is to house goby cichlids with mid-water swimming fishes. This arrangement gives the cichlids the bottom to themselves, while providing all the other advantages of having dither present in a cichlid tank. One is far more likely to observe the full range of these amusing little cichlids' behavior under such circumstances, as well as enjoy success in inducing them to spawn.

These are easily fed cichlids. They eat any food small enough to be easily swallowed. Nor do they passively wait until food hits the bottom before attacking it. Floating flakes are nailed with pinpoint accuracy in a series of high-speed sprints to the surface. Equally amazing is the sight of a goby cichlid holding position in mid-water through strenuous exercise of the piscine equivalent of the dog paddle as it snaps up live brine shrimp. Goby cichlids prosper on the same sort of diet as Julidochromis species. This is not too surprising for, as mentioned earlier, shared dental specializations suggest considerable dietary overlap in nature.

All three genera of goby cichlid practice advanced mouthbrooding characterized by extrabuccal fertilization of the eggs and absence of postrelease brood care. What sets these little cichlids apart from most other mouthbrooders is their monogamous mating system. Aquarists discovered this aspect of goby cichlid behavior by accident. When these fish were initially imported, it was assumed that they could be bred on a harem basis, like the more familar mbuna of Lake Malawi. Many battered cadavers later, disappointed breeders realized that, regardless of how many females one started out with, the end result was always a single pair of goby cichlids! Subsequent field observations (Berglund, 1978) have confirmed that these fish do live as pairs in nature. It, thus, is safe to assume that the monogamous mating system of these fish is not an artifact of captivity.

This unusual behavior in at least two instances seems related to another aspect of goby cichlid reproductive biology. In Tanganicodus irsacae (Hutchings and Hutchings, 1982) and the Zambian, or typical form of Eretmodus cyanostictus (Robinson, 1980), both parents are involved in carrying the developing embryos. The female is the initially ovigerous parent, relieved c. fifteen days into the three week incubation sequence by her mate. However, such biparental incubation cannot explain the occurrence of monogamy in either the northern form of Eretmodus cyanostictus or in Spathodus, for these fish are exclusively maternal brooders (Davenport, 1975; Gourley, 1979; Poirier, 1975). The solution to this puzzle must await a fuller knowledge of the ecology of these cichlids in Lake Tanganyika. For aquaristic purposes, however, the message is quite clear. Despite their highly developed pattern of buccal incubation, the goby cichlids must be managed in the same manner as any other monogamous dwarf cichlid.

The chief difficulty in inducing these fish to spawn is that of securing a pair. Obvious secondary sexual characteristics are conspicuous by their absence. As with the generality of cichlids, males tend to be slimmer and somewhat larger than females of the same age. There is also a tendency for older males of S. erythrodon and T. irsacae to have a somewhat more massive head than do females. Unfortunately, these distinctions are not likely to be of much help in selecting a pair from a tank of wild-caught fish. This is one situation where direct examination of the genital papillae with the aid of a hand lens is definitely in order. The size differences alluded to earlier are of some help when one has tank-reared fry to work with, but I would still advise prospective breeders to purchase a group of six or more youngsters and separate incipient pairs as soon as they are noted.

Courtship in these fishes is reminiscent of that seen in Lamprologus, comprising a great deal of lateral posturing and reciprocal opercular flaring. The female is frequently both the initiator and the more enthusiastic participant in courtship. The fish are somewhat more secretive about spawning. Typically, the cessation of normal feeding by the female is the first indication that spawning has occurred. Even this is less obvious a clue than it might seem, for most females continue to eat lightly while carrying. The eggs are yellowish-white to dark green, depending upon the diet of the female. They are somewhat discoid in shape and measure an amazing 5.0 mm in diameter. Given the size of the eggs relative to that of the buccal cavity, it is nothing short of amazing that a female can not only pack away up to 30 eggs, but actually continue to feed at all while carrying them!

As a group, goby cichlids have the reputation of being unreliable parents. This may have arisen due to initial ignorance of the biparental nature of brood care in some species. It is hardly reasonable to expect the female to carry the full burden of incubation unaided if she is normally relieved two weeks into the sequence by her mate. I also have the impression, based upon conversations with aquarists who have successfully bred these cichlids, that performance improves with experience. Unfortunately, these attractive cichlids command a ready market at good prices. Hence, many breeders succumb to the temptation of stripping females several days into the incubation sequence and carrying the embryos to term artificially rather than allow the passage of time to bring about the desired improvement in parental performance.

The incubation period lasts for 21 to 25 days over a temperature range of 25Э30у. In the biparentally brooding species, re-spawning can occur as early as five days after the release of a previous brood. This greatly reduced turnaround time is a consequence of the female's ability to feed while her mate completes incubation of the young. Females of the exclusively maternal incubators take about a month to ripen another clutch of eggs. The chunky fry measure 8.0 mm-10.0 mm TL at release.

They have the same broad-minded approach to food as their elders, but are still relatively slow-growing. It takes four to five months for them to reach 2.5 cm-3.0 cm SL. If due attention is given to water cleanliness, they are easily reared. Most losses arise from improper management of the nitrogen cycle in their aquaria. Sexual maturity is attained sometime between the tenth and fourteenth month postrelease.

The final group of Tanganyikan dwarf cichlids comprises the shell-dwelling representatives of the large Lamprologine assemblage. These dwarf species are obligate associates of empty shells of the snail Neothauma, just as the Malawian Pseudotropheus lanisticola is with those of the genus Lanistes. In both instances, the empty shells furnish the shelter that allows these small cichlids to live over open, sandy or muddy bottoms in an environment abundantly stocked with predators. These dwarf Lamprologus not only shelter in these shells, but females also use them as spawning sites and nursery areas for their fry. Given their importance to the fish, it is hardly surprising that these cichlids defend their shells with great vigor not only against conspecifics but also against any intruder perceived to be a threat to their home's integrity. The second category can include larger heterospecifics, and in a few cases, human appendages!

Table 2 lists the Lamprologus species known to live or strongly suspected of living in association with empty snail shells. It is evident at a glance that this particular life style has far more practitioners in Lake Tanganyika than it does in Lake Malawi. This might reflect a broader resource base. Possibly empty Neothauma shells are more abundant in Lake Tanganyika than are empty Lanistes shells in its southern counterpart. Alternatively, the greater number of shell-dwelling Lamprologus may simply reflect a broader base from which evolution could operate than was available in Lake Malawi. It is elearly evident at a glance that this group of diminutive cichlids is far too morphologically diverse to represent the outcome of a single evolutionary event.

Neolamprologus meeli and L. wautioni, for instance, appear more closely related to the large representatives of the L. pleuromaculatus complex of sandy shore species than to other shell-dwellers such as Neolamprologus brevis or Lamprologus ornatipinnis. Unlike the goby cichlids, which appear to represent a monophyletic assemblage, the shell-dwelling Lamprologus are polyphyletic, the shell-dwelling habit having evolded independently in several different Lamprologus lineages.

The behavior of these fishes displays as much diversity as their morphology. All are given to diving head first into an empty shell when threatened. In the absence of shelter, they will try to dive directly into the substratum. However, they differ in the degree to which they will move away from their shelter, in the amount of effort they will invest in modifying its immediate vicinity, and in the vigor with which they will defend it against perceived threats. At one extreme, Neolamprologus brevis seldom strays more than a few body lengths from its shell. It expends tremendous effort covering its shelter with sand and excavating a "patio" at its entrance. A resident will attack anything it perceives as a threat to its handiwork, including a human hand. Neolamprologus ocellatus, on the other hand, spends most of its time well up in the water column, entering its shell only when actually threatened. It expends little effort in modifying the vicinity of its shelter and displays none of the belligerence Neolamprologus brevis shows towards conspecifics.

All of this has considerable bearing on how these fish should be housed and with whom they can be expected to harmoniously coexist. The rule of thumb for any representative of this group should always be at least one shelter per fish! Shelter and Neothauma shell are not synonymous, I hasten to add. Virtually any shell of the same size and shape will be accepted by these fish. Empty shells of both the apple and mystery snails are excellent substitutes for Neothauma. So are medium-sized shells of the marine naticid or moon snails. Both Neolamprologus meeli and Neolamprologus ocellatus will accept halved 2" clay flower pots in lieu of shells, while Neolamprologus brevis finds 1" PVC right angle joints with one end closed off acceptable shelter.

Whatever one decides to offer the fish, it is a good idea to toss a few extra units into the tank. My overall impression is that these cichlids do appreciate a choice of dwellings. Spacing does not seem critical for shells. The fish usually push their chosen shelter to a spot they find congenial. Occupied shells seem to wind up 20.0 cm-30.0 cm apart in most cases. This spacing provides a guide for the dispersal of less movable shelters. I have noticed that the fish, themselves, may aggregate more tightly than these distances would suggest when not actually breeding. What seems critical to the fish is the knowledge that it has a shelter into which it can retreat in times of danger.

These dwarf species are obligate associates of empty shells of the snail Neothauma.

However tolerant they may be of conspecifics outside periods of sexual activity, one should not forget that, though small, these fish are still members in good standing of the group of Lamprologus. Prudence thus dictates housing them one pair to a tank unless large (> 200 l) aquaria are available. With the possible exception of Neolamprologus brevis, which I suspect could teach table manners to a tankful of starving piranhas, these little Lamprologines should not be housed with larger congeners. They just aren't big enough to hold their own in such company. They do quite well in the company of other Tanganyikan dwarfs and do not appear inhibited by small to medium-sized open water species such as Callochromis and Cyathopharynx. Schooling dither fish such as poeciliids or melanotaeniids are also good companions for these dwarf Lamprologines. They are not so aggressive that they out-compete their companions at feeding time, and assuming the tank they share with the cichlids is large enough, they are sufficiently agile to avoid being badly abraded when the Lamprologines decide to breed.

Once the question of suitable shelter and companions has been resolved, keeping these fish happy poses few problems. Their ordinary maintenance requirements do not differ from those of other Tanganyikan dwarf cichlids. Wild-caught specimens are sometimes less than enthusiastic about flake foods, but their tank-reared descendants devour with gusto anything of animal origin small enough to be easily swallowed. All the species to date imported are enthusiastic feeders on Artemia nauplii, while the species I have kept will gorge to repletion on Daphnia and glassworms. Their fondness for newly hatched brine shrimp is particularly fortunate, as it greatly simplifies the task of furnishing these cichlids with live food.

Of the species to date imported, four have been induced to spawn in captivity. The main obstacle facing the aquarist working with wild-caught specimens is that of obtaining individuals of each sex. Shipments straight from the Lake tend to consist largely of individuals of one sex, usually females. If, as I suspect, these fish are collected by scaring them into their shells and scooping up the occupied shelters, I such biased sex ratios may arise due to differential persistence in occupancy by the two sexes in the face of major disturbance. There is some evidence, based on observations of captive fish (Konings, 1980), that this is true for Neolamprologus brevis. Females of this species appear to be far more strongly site attached than males. In light of this, the preponderance of females in the first shipment of this species to reach the U.S. is less of a mystery. Sex differences follow the general Lamprologine pattern. Males grow larger than females, up to twice as large in some instances. They also typically have longer vertical fins, both paired and unpaired, and display a slight tendency towards frontal gibbosity. Color differences between the sexes appear to be nil.

There is no information on the mating system of these dwarf Lamprologines in Lake Tanganyika. In captivity, the best way to describe the relationship between the sexes is open. Both polygyny and polyandry have been reported for one species, Neolamprologus brevis (Konings, 1980; 1981), while Neolamprologus meeli males will spawn freely with several females. The fact that each individual defends a discrete territory in the form of a shell, taken with the size dimorphism characteristic of this group, suggests that harem polygyny is the rule for these cichlids in nature. Successful breeders of these fish prefer to set up single pairs on the grounds that fry survival under such conditions is superior to that obtaining when other adults are present in the breeding tank. A single pair can also make do in a much smaller tank. There seems to be no objections to such an arrangement from the parties most intimately concerned, though I suspect aquarists who opt for this approach will miss observing a great deal of interesting behavior. I like to use small, expendable cichlids as a combination of dither and target fish when setting up pairs of these Lamprologus. Six to eight week old convict cichlid fry are an excellent choice. Such an arrangement minimizes the risk of intramural squabbling without posing unreasonable risks to the survival of a pair's fry. If some cover is provided for them at the surface, the target fish will even live fairly uneventful lives and have a very good chance of outgrowing their usefulness.

TABLE 2. THE DWARF SHELL-DWELLING Lamprologus OF LAKE TANGANYIKA

  • Neolamprologus brevis Boulenger 1899. (1)
  • Neolamprologus hecqui Boulenger 1899. (2)
  • Neolamprologus kungweensis Poll 1956. (3)
  • Neolamprologus meeli Poll 1948. (4)
  • Neolamprologus multifasciatus Boulenger 1906. (5)
  • Lamprologus ocellatus (Steindachner 1909). (6)
  • Lamprologus ornatipinnis Poll 1949. (7)
  • Lamprologus signatus Poll 1952. (8)
  • Lamprologus wauthioni Poll 1949. (9)
  • Lamprologus sp. indet. (10)

(1) This species made its American debut in 1979. It has been bred successfully in Europe, but not to date in the U.S.

(2) Preserved material attributed to this species displays considerable variability in color pattern. This name may currently be applied to more than one species. Not imported to date.

(3) Easily recognized by the presence of a large, ovoid black spot in the posterior portion of the soft dorsal fin. Not imported to date. (4) Imported into the U.S. concurrently with Neolamprologus brevis. First member of the group successfully bred in this country.

(5) Not to date imported into the U.S., although I saw a similarly colored fish in England in the fall of 1981.

(6) Made its American debut in the early 1970's. Bred at that time but not successfully established in the hobby (T.J. Koziol, pers. comm.). Reimported concurrently with Neolamprologus brevis and since bred in the U.S.

(7) Isolated specimens have come into the U.S. as "contaminants" in shipments of Lamprologus ocellatus. Not bred to date.

(8) Possibly imported into the U.S. in 1981 (See Figure 10.) The species in question has not spawned to date in captivity.

(9) Similar in morphology to Neolamprologus meeli, but characterized by a well-developed reticulate pattern in the soft dorsal and caudal fins. Not imported to date.

(10) Sold under the trade name of "Lamprologus magarae," this species made its American debut in 1981. It has bred successfully in captivity.

After a somewhat perfunctory courtship, which she may well-initiate, the female deposits a clutch of eggs well-inside her shell. Here they are fertilized by her consort. In the case of Neolamprologus meeli, the male's dimensions relative to those of the spawning site raise some intriguing questions about precisely how this is managed! Once he has accomplished his essential function, the male becomes superfluous in captivity. I suspect in nature, he may provide long-range defense of the fry by interdicting at least one series of approaches to the female's territory through an enhanced defense of his own. Care of the eggs and wrigglers is exclusively maternal and the male's proximity to the spawning site is actively and effectively discouraged by the female. So is that of any other fish present. Her abilities in this direction are largely a function of the outsized dentition that comes as standard equipment in all Lamprologus species. Hence the injunction to use only expendable target fish in the breeding tank.

At 25Ь the fry hatch 60 to 72 hours postspawning and are mobile four days later. They may not leave the interior of the shell until the ninth or tenth day postspawning, however. Thus it is a good idea to offer the female Artemia nauplii as soon as a spawning is observed. Any she might miss will be available as food for the fry whenever they are ready for it. The fry measure 5.0 mm-7.0 mm TL and appear quite large-headed. They certainly have capacious mouths. Artemia nauplii are engulfed with hardly a pause by newly mobile fry, while Neolamprologus meeli three days free-swimming can take newly dropped Daphnia. Contrary to the usual rule with Tanganyikan cichlids, these dwarf Lamprologus grow quite rapidly. They typically attain sexual maturity, though not their full adult size, within six months postspawning. Konings (1981) reports an amazing three months from spawning to sexual maturity in Neolamprologus brevis.

All available accounts of the spawning of these little cichlids (Ferguson, 1981; Konings, 1980, 1981; Robinson, 1981) emphasize the exclusively maternal brood care and complete lack of any schooling tendency on the part of the fry. As is the case with Julidochromis, what the female seems to defend is the immediate vicinity of the shell, rather than a swarm of mobile fry. As long as the fry remain within the vicinity of the shell, they are effectively protected. Brood care appears to be determinate, persisting for two to three weeks. As she begins to ripen a new batch of eggs, the female will chase her earlier brood away from the shell wherein they hatched. The male usually tolerates those that move into his territory. They, thus, appear to enjoy some measure of continued protection in consequence of its defense. It is usually best to anticipate these events and separate mother and fry after the latter have become mobile if one wishes to raise the maximum possible number of fry. The young, themselves, become territorial at a very early age. This behavior can lead to losses due to intersibling aggression unless the rearing tank is well-furnished with shelter. Rearing is otherwise as for any other Tanganyikan dwarf cichlid.

The shell-dwelling Lamprologines are my personal favorites among the Tanganyikan dwarf cichlids. While not spectacularly colored, they are personable little fishes whose behavior is truly fascinating to observe. As John Ferguson, an English friend, put it: "They have character". A quick glance at Table 2 will confirm that the full potential of the described representatives of this group has hardly been exploited. The importation of Lamprologus "magarae" bears out in a most trenchant manner Pierre Brichard's prediction, made at the American Cichlid Association's 1978 Annual Convention, that both ichthyologists and aquarists could anticipate future surprises from this group of species. I feel quite safe in predicting continued interest in and substantial popularity for these newest Tanganyikan dwarf cichlids.

Neolamprologus brevis

Literature Cited

引語:

Loiselle, Paul V.. (九月 06, 1997). "African Dwarf Cichlids, the Lake Tanganyikan Species: Part Two". 慈鯛魚室同好網. 檢索 十月 20, 2014, 來自: http://www.cichlidae.com/article.php?id=61.