‘Lamprologus’ signatus displacement

Adult male ‘Lamprologus’ caudopunctatus. Photo by the author.

Adult male ‘Lamprologus’ caudopunctatus. Photo by the author.

If you’re a regular reader, you know two of my show tanks are 75g. One of the them is a Tanganyikan community tank, which you can find plenty of info about if you do a search here. The other tank started out as a Malawi mbuna tank several years ago. However, in the last couple of a months I’ve turned it into a mixed mbuna/Tanganyikan shellie tank. Generally, mixing Lake Malawi cichlids with those from Lake Tanganyika is frowned upon for a variety of reasons (e.g., diet differences, water parameter differences). However, it can be done just fine if 1) you know what you’re doing and 2) you have the right mix. But what about water and diet, you ask? My water is naturally alkaline and hard, so that’s a non-issue. I’ll get to the diet in a minute. 

There are only two mbuna in the tank now – a adult “red top” Hongi (Labidochromis sp. hongi) and an adult yellow lab (Labidochromis caeruleus). These are rock dwelling cichlids endemic to Lake Malawi. About a year a go, I added a pair of Lake Tanganyikan ‘Lamprologus’ signatus (not wild caught) and several shells. I lost the female shortly after adding her to the tank when she decided to check out my drain hose while when I turned my head. So for roughly the past year, the lone male has shared the tank with the two mbuna.

I watched their interactions because I wanted to see how the male signatus, which is about 10x smaller than either mbuna, would react. Naturally, at the beginning he would duck into his shell any time one of the mbuna cruised by. But over time, he became less and less frightened and, in fact, would chase them off if they got too close. The two mbuna? They paid zero attention to him. Mbuna are algae grazers primarily, and these two have zero interest in the signatus as food nor do they see him as any kind of threat. 

Fast forward to about six weeks ago, and I decided to add a couple of more shellies to the tank. I had grown out a spawn of ‘Lamprologus’ caudopunctatus 30g. So I plucked a couple of near sub-adults (one male and one female) from their tank and placed them with the mbuna and signatus. Again, the mbuna paid no attention to the caudos. While the signatus wasn’t overly thrilled, he made his presence known, keeping the two smaller caudos at bay. 

Because I also had two adult males in the 30g caudo tank, I decided to move one to the above 75g with the signatus and two other juvenile caudos. Wow, how quickly things changed. The adult male caudo that I moved to the 75g took no time whatsoever to displace the lone signatus. Adult male caudos, while still not very large (~1.75″), are larger than adult male signatus. Fortunately, it’s a large tank and there is plenty of room.

The signatus quickly found a new home in an escargot shell at the opposite end of the tank from where he was (see the bottom photo above), while the large adult male caudo set up shop on the opposite end. In the top photo above, you can see a shell inside half of an upturned clay pot on the right end of the tank. This used to be the signatus‘ home. While the large male caudo didn’t want the escargot shell, he did want the space around it including the muffin shell next door (see the shell directly behind the caudo).

Since that day, the adult male caudo stays on the right end of the tank, which he’s claimed as his own, and the signatus stays on the left end. As to the interactions between the adult male caudo and the mbuna, there isn’t any. The mbuna pay not attention to him and, in fact, he pretty much doesn’t move when they get near. 

Regarding the diet for a mixed mbuna/Tanganyikan shellie tank, there are two important points to remember here. One is that the shellies are much smaller than the two mbuna. That means they eat much less, so I don’t have to put much food in for them. I give the mbuna pellets or large flakes, which occupies their attention while the shellies eat the much smaller flakes. The algae/spirulina-based food for the mbuna won’t hurt the shellies if they consume some of it and is actually beneficial. Because there is such a small volume of higher protein, animal based food for the shellies, it poses no threat to the mbuna (think Malawi bloat here). Furthermore, I only feed my fish once a day. 


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