I picked up a group of Metriaclima lanisticola at the auction of the OCA Extravaganza 2009. I was drawn to them because of their shell dwelling behavior. I love the shell dwellers of Lake Tanganyika, and had not heard that this behavior existed in Lake Malawi - until this bag of fish came up for auction and the announcer called them "Malawi shell dwellers". It was toward the end of the auction, the price was right, and so I was suckered into making an impulse buy. In all the pictures of M. lanisticola I have seen on the net, they look like very drab, brown fish. As you can see, mine are quite colorful – especially the dominant male.
Chester B, who also kept a group of Metriaclima lanisticola, contributed to this article, and reported that his fish showed a little more distinction on the black and white edging on the fins and tail, and younger fish displayed more of the barred pattern and had much more yellow in the body and fins. His dominant male had the same metallic blue over olive background as mine, who is shown in the photos.
At the time of taking the pictures, I had only gotten one single fry, but that changed quickly, and the colony became quite prolific, as did the Labidochromis caeruleus sharing their 75G tank. They show about the same level of aggression, meaning together with Iodotropheus sprengerae they are about the least aggressive mbuna there are. The whole shell dwelling thing with Metriaclima lanisticola is a bit overrated. Possibly some Malawi nut could no longer cope with the fact that only Lake Tanganyika has shell dwellers, and they made the whole thing up. Kidding aside, they breed like any mbuna, meaning they are maternal mouth-brooders and it would be hard to stop them from breeding! The adults of my colony showed no interest whatsoever in shells, pipes or caves. Only about 1/3 of the fry in my colony were shell dwelling at a young age. Curiously, the other 2/3 of the fry did not stay at the tank bottom like most mbuna fry, but preferred to hide in floating plants at the top of the tank - a behavior that I had only observed with life-bearer fry like Xiphophorus. Chester B reported all his fry/juveniles used shells for cover. The bigger the shells the better. I assume that the peculiar behavior of my fry might have been caused by an abundance of plants, including floating plants, in my tank, which is quite untypical for a mbuna setup. Metriaclima lanisticola fry show an interesting striping pattern, and look quite similar to little Tropheus.
Metriaclima lanisticola has another intriguing characteristic that in my opinion makes shell dwelling look pretty ordinary – they can do a complete sex reversal! Dr. Jay Stauffer was able to show this in a peer-reviewed, scientific paper (Stauffer, J. R., Ruffing, R. A., Copeia 2008, No. 3, 618-620). In a nutshell, his research group took proven females, that is fish that had laid eggs and carried them in their mouth, and put them in a separate tank. Eventually breeding was observed and fry were obtained from a tank containing only such proven females. This shows that at least one fully functional female had turned into a fully functional male. The paper refers to the fish as Metriaclima livingstoni, which is an old name for Metriaclima lanisticola.
Chester B had good success keeping his colony in a 3' tank. Mine were quite old when I got them, and due to the size they eventually reach, I would hesitate to recommend them for tanks under 4' in length, but they make great tank mates for other less aggressive mbuna species like Labidochromis caeruleus and Iodotropheus sprengerae. I have not regretted the spontaneous purchase I made at the 2009 Extravaganza, and Metriaclima lanisticola have become one of my favorite mbuna species overall. Metriaclima lanisticola can show great coloration, especially in the males, and they exhibit interesting behaviors, which makes them well worth keeping for beginners and seasoned mbuna keepers alike.