Magical mbuna

Fishkeepers the world over struck gold with the introduction of the small colourful rock-dwelling cichlids from East Africa’s Lake Malawi.

The Mbuna as they are known (pronounced mmm-boon-a or mu-boon-a,) are hardy, easy to keep, easy to breed, collectable, yet at the same time widely available.

One qualification any aquarium fish needs to become really popular is colour, and the mbuna deliver this in spathes. Yellow and orange are common mbuna colours but importantly, and rarely for any wild-type tropical fish is blue, and this is where the mbuna excel, with literally hundreds of bright blue or blue patterned species, which have tricked many an onlooker into thinking these totally freshwater fish are in fact marine.

Next is the number of species which you can keep together. No other aquarium is capable of holding as many different species of fish per volume as a Malawi cichlid tank. An average mbuna community could hold 30 different species – a large tank 50 or more.

You wouldn’t be able to keep 30 Central American species in one tank, it would be chaos, even a community tank holding fish from many different, very varied genera would struggle to hold that many because so many species need to be kept in groups of their own kind, but not the mbuna, and this all adds to the overall appeal.

Mbuna in nature

To keep mbuna at their best first we must look to how and where they live in nature. Mbuna are endemic to Lake Malawi in Africa’s Great Rift Valley – a 3700 mile long trench created by the African tectonic plate tearing apart.

Malawi is a gigantic crevice which filled with river water and its fish, which then changed, evolved and adapted to suit the new, lacustrine environment. 

But don’t think local boating lake here, or even Lake Windermere – Malawi is the ninth largest lake in the world and the second deepest, at 706 metres. It’s 360 miles long, 50 miles wide and some 11,000 square miles in area. That’s bigger than Wales…

A lake of that size comes complete with waves, rocky cliffs, sandy beaches and tales abound of early explorers mistaking it for an ocean, which let’s face it, you would. 

Cichlids entered Malawi via its tributaries, with two tribes – the Tilapiines and the Haplochromines, taking up permanent residence there. Things got interesting for the Haplochromines however, who went through “adaptive radiation” and today comprise around 1000 species, which is about as many species as live in the whole of the North Atlantic.

This was great news for human populations who could then fish the lake for food, scientists who study evolution, and of course us, who get to marvel over Malawi’s bountiful beauty in our home aquariums.

So think freshwater reef fish and you would be about right, as the colourful yellow and blue mbuna we keep bask in the clear blue, sunlit waters and live in and around the rocky outcrops. Cichlid paradise!

Maternal mouthbrooders

But the fascination doesn’t stop there, as the mbuna deliver a double whammy of appeal by way of how they breed. All the mbuna, and all the other haplochromines in Lake Malawi are maternal mouthbrooders, meaning that they lay eggs which are then taken into the female’s mouth where they are incubated, hatched, and then finally spat as fully formed, (quite large by fish standards,) fry. 

This paid dividends for the early cichlid colonisers of the lake bed as even breeding females were not tied down to anyone small patch for a month at a time and instead could be upwardly-mobile, go forth and colonise.

The uninitiated won’t know that a female can be with eggs or fry at all, and the males didn’t have to turn into giants who would then have to defend the fry against all comers – be they fish, bird or reptile.

The mouthbrooding phenomenon doesn’t just happen in the wild. Keep mature males and females together in the home aquarium and they will breed, as long as they don’t kill each other first that is. And for many mbuna keepers the progeny can provide a useful supplemental revenue stream. 

Keeping them at home

The good news about mbuna is that although there are so many species they can all be kept in exactly the same way, eat exactly the same food, and once you conquered keeping them for the first time you can mostly keep any of them. As long as you observe the fundamentals.

Coming from such a large lake the mbuna are used to clean, clear water which is free of pollutants and rich in oxygen.

For the aquarium this means they need lots of mechanical and biological filtration, lots of water changes to keep the bi-product of biological filtration- nitrate at low levels, and extra aeration by way of an airstone or venturi outlet on a filter. 

Next is the chemistry of the water. All that tectonic plate activity under the lake has meant that Malawi is very rich in minerals which give it a high pH, KH (carbonate hardness,) and GH (General hardness.)

Those with scaled-up kettles and hard tapwater will do really well with mbuna. But these aren’t fish for soft, acidic water conditions so no to reverse osmosis water without adequate amounts of malawi cichlid salts first being added. And decor should include calcareous, lime-based decor or filter media to keep those minerals high and pH, KH and GH buffered.

Tank size

In the wild mbuna rarely top 3-4” total length but fed rich foods in the aquarium they can reach 5-6”.

They are aggressive and territorial and you need to keep lots of them, so a large tank is a must. To start right with mbuna a four foot tank or larger is best. Yes breeders and the shops keep them in tanks as small as two feet but this ability comes with experience, and it’s far from ideal.

Some species are classed more as dwarf mbuna, which we will cover later, and these could do well in a tank of 36-40”, but even then a taller, wider tank with a volume upwards of 180 litres is best. When creating a home for mbuna try to replicate the lake environment, being deep and wide.

A 4x2x2’ will be much more conducive to the lake theme and effect than a 4x1x1’, which holds a quarter of the water and is much better suited to replicating a small, shallow stream.   

Species selection

Getting started with mbuna can be somewhat of a trap for the uninitiated, as the most widely available species are nearly always some of the least suitable to get started with.

Melanochromis auratus is probably the most widely available species, with juveniles displaying attractive humbug patterning, and it is a very hardy, durable species. But at the same time it is also one of the most aggressive species and will quickly dominate, then terrorise a new, sparsely populated tank.

Males and females become duller and more dirtier marked too, losing much of the bright white, bright yellow and clear striping. 

A first foray into blue fish can also be folly, with Pseudotropheus socolofi being an attractive powder blue in colour but again getting aggressive and quite large with age. And Metriaclima lombardoi starting life as blue vertical banding on both males and females, males then turning a lovely bronzy yellow with maturity but also developing a foul temper.

Add to that a few unidentified hybrids and you’ll have a very aggressive, real nasty tank which will be anything but relaxing to watch.

Instead seek out a cichlid specialist who will have more species and better labelling. There you will be able to buy bright yellow but mild in temper Labidochromis caeruleus and dark blue but small in size and temper, Melanochromis cyaneorhabdos. Add a group of lilac coloured Pseudotropheus acei and they are the least mbuna-like mbuna at all, being generally placid. 

Large aggressive species

Melanochromis auratus

Pseudotropheus socolofi

Labeotropheus fuelleborni

Metriaclima lombardoi

Metriaclima crabro

Metriaclima greshakei

Smaller less aggressive species

Labidochromis caeruleus

Melanochromis cyaneorhabdos

Pseudotropheus acei

Melanochromis joanjohnsonae

Labidochromis perlmutt

Labidochromis freibergi

Pseudotropheus perspicax

Melanochromis dialeptos

Pseudotropheus livingstonii

Crowd pleasers

Metriaclima pulpican (barred zebra-like species)

Labidochromis caeruleus yellow (bright yellow males, female and fry)

Metriaclima estherae (orange females, powder blue males, OB males and females)

Orange blotch (OB) zebra (calico, shubunkin-like, naturally occurring colouration)

Pseudotropheus elongatus “Mphanga” (small but feisty. Stripy and colourful)

Cynotilapia afra (classic dark blue vertical bars and bright heads and dorsal fins) 

True Metriaclima zebra and similar species (males display vertical barring which give the zebra complex their name)

Stocking

So we know that male and female mbuna don’t form mated pairs, but that does mean that male mbuna can be troublesome. To anthropomorphize, male mbuna would like nothing more than to be the only male Haplochromine in the whole of Lake Malawi, or better still, the whole of the world.

Males want to adorn themselves in the brightest colours and live over the best real estate, and heaven is to be visited every ten minutes of every day by a female looking for a casual fling, who then disappears, never to be seen again. 

Hell for a male mbuna is to be surrounded by other males, other better looking, more masculine males, who then eat their food, take up residence in their space and worst of all, take all their women.

This results in a typical male response – fighting – and females who don’t know when to leave will get battered too. If you’re three inches long and aquatic, never get within a few metres of a male mbuna with a rage on. It will hurt.

But our tanks are only a metre, a metre and half long at best, so knowing what we now know about mbuna psychology, we have an anger management problem we need to address.

Rival males and non sexual females will always be in the vicinity of  dominant, sexually charged males, so it’s how we deal with it which will make or break your mbuna “community”.

Decor

First is decor. Where the mbuna live in Malawi the rocks would need moving with a JCB, but we can use lots of smaller rocks, say 5-6” across, in piles in the aquarium. A rock gives a male something to call his own, somewhere to feed, and breed and if you use a limestone rock it will even buffer your water and help to make water hard. 

Pile the rocks together and females, fry and subdominant males can take shelter in the crevices and get out of the line of sight of the aggressive male. He won’t punch you if he doesn’t know you are there.

Next you can pile rocks high to further obscure the line of sight across the aquarium. Make a visual barrier and two males will separate and coexist, each defending their own now tiny territory. Add lots and lots of rocks and you can give lots of males lots of territories to call their own.

The next stocking aid is to overstock. You have lots of filtration and lots of aeration, so go wild (filter bacteria levels permitting,) and quickly build up a high number of similarly sized, similarly aged (ideally young, sub 5cm fish).

Twenty individuals is an absolute minimum, but 30 or 40 is even better. Grow them up crowded, where they all know each other and anger can be managed. Outnumber a male of each species by at least two females, so one poor female won’t get singled out and harassed. Or don’t have any females at all, although you will miss out on the joys of breeding. 

Like a Cockerell with a group of hens the one thing that is really going to wind up your male is another rooster of his own size and kind. He will fight to the death to protect what is his and the newly introduced, disorientated male will always come off worst. Passing on one’s bloodline is absolutely key in nature and overpowers every other emotion or driver. 

Overstock and the aggressive male can’t spend too long away from his rock chasing other fish as another fish could take up residence while he is away (or so he thinks so,) And that’s how Malawi mbuna tanks work.

Feeding

In nature mbuna feed on aufwuchs, an often read and often mispronounced german word meaning surface growth. This surface growth on the rocks consists of short strands of algae, biofilms and tiny critters living within it. At certain times of year mbuna will also graze on zooplankton blooms higher up in the water, and massive scale midge hatches which rise up hundreds of metres above the lake, like huge plumes of smoke when those midges hatch and mate.

For the Malawi cichlid geeks it’s the subtle specialisation of the 1000 species when times are tough and food lean which is so fascinating, as, like Zebra and Wildebeest on the Savannah which coexist by each eating different lengths of grasses, the mbuna also do so by eating different lengths of aufwuch and grazing it in different ways.

The underslung mouths of the Labeotropheus mean that they can access and rip off the best algae growths in choppy water with very little levering, keeping their bodies flat against the rocks as they do so. But take a more insectivorous Labidochromis and they have to turn their bodies headfirst, at 90 degrees to a flat surface, and then expend more energy ripping at the algae. 

So in the lean times, each species uses its specialisation, be it for eating short algae, long algae, invertebrates, insect larvae, eggs, scales or even fry. And that’s how come there are so many species in Lake Malawi versus millions of individuals of one species. Adaption means that you can occupy feeding niches that others cannot, and ultimately survive. 

In the aquarium, these specialisations are virtually never called upon, and instead, mbuna grow big and fat on rich diets and regular feeds. This then gives rise to the so-called “Malawi bloat” although many other underlying factors probably also contribute to the disease. When a mbuna has bloat its neck and stomach area become swollen and firm to the touch. The eyes pop slightly and the illness is quick and almost always fatal.

Popular advice is to avoid rich foods aimed at South American carnivorous cichlids and instead offer mbuna specific diets which contain lots of algae, vegetable matter, and low animal protein. Frozen bloodworm is advised against, and attributed to causing bloat, although it is actually very low in protein and instead high in chitin, and mostly water. 

Don’t feed anything for one day a week and your mbuna will take to the rocks, clearing up algae and clearing out their systems. 

Hybridisation

Mbuna will hybridise in the aquarium and for the sake of other mbuna buyers, this should not be encouraged. Don’t keep females without a male of their own species in the community and if the fry are suspected to be of hybrid origin don’t spread them in the hobby.

Although exciting to some, a new species won’t be created and instead of that world record-breaking cichlid diversity will be watered down and diminished, and those unique colours, patterns and specialisations will disappear.

What has caused the speciation in Lake Malawi?

Apart from the many feeding niches populations of rock-dwelling mbuna have become genetically distinct, and separate species from one another due to isolation. Periods of growth and shrinkage of the lake’s shoreline and islands have left mbuna populations cut off from one another by areas of deep, open water.

Despite being able to breathe underwater and travel with fry, a 3” mbuna is about as likely to swim alone over a stretch of 700m deep, predator filled open water as I am.

 

Image Sarah Depper, Creative Commons

  

 

     

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