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During the discussions leading to this article, I enquired of your Editor how he would define dwarf mbuna, especially what upper size limit. 'Dunno, you're the cichlid expert, I leave that sort of thing to you.' Editors are so helpful!!! But I think establishing what we're talking about is a good start here, as I personally wouldn't regard any mbuna as dwarf cichlids in the usual sense, hence my original enquiry.
Many years ago I attended a lecture on dwarf cichlids by Paul Loiselle, in which he defined a dwarf cichlid as follows:
1) Maximum (total) length 4 inches;
2) Peaceful enough and otherwise suitable to be kept and bred in a general community tank.
OK, so point 1) gives us a starting point on size, but where 2) is concerned we can immediately strike all mbuna. And Paul in fact went on to say that his definition immediately ruled out everything from Lake Malawi and Central America. That was in 1981, and although I know that a number of small mbuna, smaller than anything known back then, have been discovered since, I've not yet seen any reason to argue with his statement. It is possible to keep a single adult mbuna of some -- even most -- species in a general community, but the moment you add another one, same species or different, trouble is likely to break out.
So, regrettably, we can forget about the conventional concept of a dwarf cichlid when defining dwarf mbuna. We are instead really looking at smaller than average mbuna.
Four inches TL is nevertheless a reasonable 'cut-off' point for defining dwarf mbuna, as we need to establish some sort of size delimiter.
The next question is, however, are we looking at normal, natural (wild) size or aquarium size? Wild mbuna have quite tough lives, they have to survive on an often impoverished diet, and they get a lot of exercise moving around feeding and darting away to safety when they accidentally stray onto the patch of an aggressive territory-holder, which happens all the time. Sometimes they have to contend with strong currents or other turbulence which make swimming hard work.
By contrast, tank-bred mbuna have it easy. A rich (usually too rich) diet is delivered frequently (usually too frequently) by a doting owner, and instead of feeding all day they get rather more than the food they actually need in a few short sessions. Once they have settled down and established a 'peck order', there isn't generally too much chasing except when a female is ready to breed. So all that food is converted into growth.
Not only that, but over generations of captive breeding mbuna tend to become less aggressive. This is probably because killing your female(s) is not a good survival characteristic; so while a powerful male, able to hold territory and thus get to breed, is at an advantage over weaker males in the natural habitat, the reverse is true in captivity. It is rare for a captive male to have to compete for females against conspecifics, we usually keep just one male, to avoid constant warfare. So the less aggressive male who doesn't regard unripe females as enemies on his patch is at a genetic advantage in the aquarium.
The result is couch potato males that can achieve a length significantly greater than their wild counterparts.
To take one example, Metriaclima estherae, the Red Zebra. This fish can easily attain 4.5' TL in captivity, but although I've handled about a hundred caught at random for genetic sampling (fin clips) at Minos Reef in Mozambique, not one was more than 3' long. The first imports I ever saw, back in the 1970s, were more like 2.5'. Wild M. aurora (also sampled) never exceeded 4'. But how many of us think of any Metriaclima as a dwarf?!
Then there is Metriaclima lanisticola (still better known as M. livingstonii), which has a long north-south range and measures about 3' maximum in the north increasing to 6' in the south. What are we to do with that, especially as the small-size populations seem to be more aggressive than the large ones!
The whole thing can also work in reverse. Repeated brother-sister matings over many generations can lead to a reduction in size, often with other 'faults' such as melanism thrown in. We don't see too much of that though, as serious hobby breeders know better, and most tank-breds are farmed. But I have seen Labeotropheus fuelleborni reduced from their normal 5-6 inches to less than four, black, and blind after six generations of non-selective inbreeding. Such fishes are not dwarf mbuna, they are abominations and you really don't want anything to do with them.
So, returning to the question of the size limit for 'dwarf', I think the answer is to look at wild size, as otherwise I'd have to rule out practically every known species, and the few that remain may well rule themselves out after a few more generations of the good life in captivity.
Small is not always peaceful
So, what can we expect of our dwarf mbuna in terms of behavior? Does their small size mean they are less aggressive than the larger species?
The answer, as with so many things cichlid, is yes and no!
Size is never a reliable indication of behavior where cichlids are concerned, and although Kribs (Pelvicachromis pulcher) are generally regarded as dwarfs, I would observe very carefully any community into which I had placed them, having seen one pair keep six four-inch Uaru (Uaru amphiacanthoides) confined to one upper corner of a 48' aquarium and take turns to go over and issue reminders. By the same token, some quite large or even very large cichlids can be ludicrously peaceful. My Uaru didn't even try to fight back!
Temperament in fishes (and other animals) is normally inherited and evolves to match environmental pressures. Thus a cichlid that doesn't have to compete much for food and space in the wild is liable to be peaceful (except maybe when defending young), while one that has to fight tooth and nail to survive is going to have an aggressive, territorial outlook on life. As most Malawi enthusiasts will know, the amount of rocky habitat in the lake is limited and occupied by a high population density of mbuna which apparently have a psychological inability to cross sand or mud to find somewhere less crowded. Hence wild mbuna are in the main competitive (= aggressive), and even when this survival characteristic has been reduced by the aquarium good life, there is still enough of it left such that they can never really be termed peaceful.
Small cichlids from a competitive environment often come with 'attitude', just like small people do. They are at a size disadvantage when it comes to holding their own, so they are often territorial out of proportion to their size. It is a big mistake to assume that smaller means more peaceful. This is probably why we see 'inverse territoriality' in the species I mentioned earlier, Metriaclima lanisticola. The small populations come from relatively highly populated habitats, the largest come from the small Lake Malombe south of Lake Malawi, where there isn't much competition at all. Cynotilapia look like small Metriaclima ('zebras') but in my experience a 'Cyno' can see off a Zebra without problem, even though larger size is often a deterrent to attack!
Of course, because they are cichlids and their role in our lives is to confuse and cause us problems, there are also small mbuna that are peaceful, eg Labidochromis. To sum up, never make any assumptions regarding behavior based on size alone. It is probably safer to assume small means stroppy if your 'homework' before purchase doesn't reveal anything on character.
Having established what we are talking about under the heading 'Dwarf Mbuna', let us now look at some individual genera that contain such fishes, and some of the relevant species they contain.
Members of this genus 'top out' at 3.5-4' in males, with females usually smaller. As already mentioned, small does not necessarily mean peaceful, and 'Cynos' exemplify this. They are plankton feeders in the wild, but because territorial males are highly possessive of their domains they have 'algae gardens' -- ungrazed areas of algae -- around their caves. That means they are successfully seeing off even much larger algae-feeding mbuna such as Labeotropheus and Petrotilapia - no mean achievement.
Non-territorial males and females are usually found in shoals where the food is; but trust me, the moment you give a non-territorial male the opportunity to be territorial in your tank, he is going to grab that opportunity. These are gorgeous little mbuna, but they are more suited, temperament-wise, to a tank of larger mbuna of similar disposition. They are more than able to look after themselves.
Iodotropheus and Labidochromis
Members of these two genera are among the most peaceful of the mbuna. Males don't hold permanent territories where females will know where to find them when ready to spawn; as far as I know it's simply a hit-and-miss case of 'boy meets girl', and if girl is ripe, they spawn. This is a very different lifestyle to most mbuna.
Their feeding strategy is also important. Because they require no breeding territory, they move constantly around the rocky habitat and are apparently rarely attacked, probably because they are recognized as harmless non-competitors. Most Labidochromis species feed by winkling invertebrates out of cracks, and have thus found a specialized feeding niche with little or no competition from other mbuna species. They are often found in large caves -- not the habitat of the algae-grazing mbuna, so again less competition.
The algae-feeding Labidochromis are more difficult to explain. We do not know which feeding method came first, but my guess is that the algae eaters evolved from the insectivores. Their niche is an opportunistic mouthful of algae here, another there, as they wander through the habitat. It is easy to see how this behavior could have developed, maybe when insects were short supply, and would not provoke attack from territorial herbivores used to 'Labs' just 'passing through'.
Iodotropheus are also algae-feeders but again do not stop long enough to cause offence to any territory-holder. Perhaps they evolved a mobile way of life because they were unable to compete effectively for territory, as both known species (sprengerae and stuartgranti) have very limited distributions and may be survivors of once more widespread species that have been outcompeted elsewhere.
Aggression is neither necessary nor desirable where there is no competition and no need for defense; if you rely on being harmless to earn your living, picking fights would not be a survival characteristic.
Members of this genus generally have a bad reputation for being hard on females, but there are in fact several small species that are not in that mold. These include the well-known M. joanjohnsonae and what I term the M. johanni group -- johanni, interruptus, cyaneorhabdos. The latter three are smaller and more peaceful than most of the genus and the first two of them have orange rather than banded females. I am convinced that they are actually members of a separate genus (or genera) as although they conform to the current definition of Melanochromis, the horizontal bands are in quite different positions to in M. auratus, for example. I don't think joanjohnsonae belongs in the genus, either! M. dialeptos is also smaller than my 4' limit and looks very much like a small auratus.
The territoriality of these species seems to be variable -- I have read in several books that johanni isn't territorial, and mine were quite peaceful, but I have watched some real battles between males in the lake. Answer, keep one male and nothing else with a similar provocative stripe pattern, as with all banded Melanochromis.
The majority of the members of this genus are far too big to fall into the dwarf category, but a few do, notably M. sp. 'membe deep' from Likoma, and M. sp. 'msobo' and M. sp. msobo heteropictus' from the Tanzanian shore of the lake. The 'Membe' is really small (three inches in males, one of the very smallest mbuna) There is a question mark over whether these three belong in the genus at all as their coloration isn't at all characteristic, and some authors put them in Pseudotropheus (where they certainly don't belong, see below). They are territorial like other Metriaclima and tend to 'attitude'.
As mentioned earlier, some other Metriaclima also conform to the size limit when wild-caught, and in my experience are relatively peaceful, more so than the three listed here.
Pseudotropheus is polyphyletic, in other words its members are not all descended from a single species as the definition of a genus requires; this is scientifically recognized and hence the genus is slowly being broken up into separate genera. At present it contains a large group known as the 'elongatus group' (all elongate and slender) and a lot of 'odd' species whose generic status is largely a mystery.
The elongatus group contains a fair number of dwarf species, mostly undescribed, the best known being Ps. 'elongatus ornatus' or just 'ornatus' and Ps. flavus, better known as Ps. sp. 'dinghani'. The group comes with a big 'but' -- I am convinced that these elongate mbuna are not all closely related and probably belong in at least two separate genera. In my experience those with no bars between the eyes grow larger and are considerably more aggressive (sometimes downright murderous) than the smaller species with interorbital bars and a fairly civilized temperament. So while there are 'dwarfs' here, don't make any rash assumptions on the basis of the name.
One of the best known and most popular of the 'oddments' is Ps. demasoni, a true dwarf that attains only about three inches. It is non-territorial in the wild, though may occupy territory if given the opportunity (no competition to keep it in its place) in captivity. This is, however, perhaps the only species that can be termed a true dwarf in the traditional sense of very small and peaceful.
The genus contains a number of other species of similar small size - for example Ps. minutus, Ps. sp. 'polit', Ps. pulpican, and Ps. saulosi -- but less equable temperament, ranging from rather to very territorial.
Ps. pulpican deserves a special word of explanation. You may also find this species as Cynotilapia and Pseudotropheus in the literature, and the species name will probably mean nothing you at all until I tell you that this is the little cichlid we have known for decades as Kingsizei! It looks like a Cyno, feeds like both a Cyno and (mainly) a 'zebra', and its teeth don't fit with either.
Moving up slightly in size we have Ps. heteropictus (3.5', aggressive) and the well-known Ps. socolofi (4', rarely aggressive). Tank-bred Socolofi are, of course, significantly larger, but usually peaceful compared with many smaller species.
So where does all this leave us? Well, essentially dwarf mbuna aren't substantially different to other mbuna, they are just smaller. They may well be over-aggressive for their size, and need just as much space as larger species. So if you were dreaming of a 24' mbuna community filled with peaceful dwarf species, please forget it!
Konings, A. 2003 Back to Nature Guide to Malawi Cichlids (2nd edition). Cichlid Press, El Paso, USA. 208 pp.
' ' 2007 Malawi Cichlids in their Natural Habitat (4th edition). Cichlid Press, El Paso, USA. 424 pp.