Demasoni or better known by its scientific name of Pseudotropheus demasoni is a type of tropical freshwater fish that belongs to the mbuna cichlids (substrate dwelling) group which originates from the Lake Malawi in Africa. So far there are two different variants of the same species one called the Pombo Rock and the other one known as Mozambique or sometimes called midnight demasoni, whereby both fish were actually named after the area of the lake from where they were caught from. Both types of cichlids look almost the same except that the color of the Mozambique variant is more towards faint purplish while the Pombo Rock which is more commonly seen sold in aquarium shops has darker blue stripes. One should never confuse and wrongly identify the fish to be similar like the other zebra Malawi cichlid as all of them bear some close resemblance compared to each other and sometimes it would take an expert hobbyist to really figure out the difference between them and correctly identify which group belongs to which.

It is recommended that the aquarium capacity should be as large as possible (above 50 gallons tank would be nice) so that there is less competition among them going against each other for foods and living space. Usually with the tank volume, that is enough to accommodate at least 3 of the same fish species but serious hobbyist will usually buy more up to 4 or 5 so that they can be sure that they will end up having at least one mating pair. The ideal condition would be having one male fish while the rest up to 3 are all females. If by any chance you ended up having two males in a group, I would suggest removing the less dominant one so that it will not get bullied all the time. Other options would be, you could even set up another active pair if you have an extra tank to spare so that they can reproduce away from the attention of the other competing fish. Don’t worry about having to deal with so many fry because anyone would be tempted to have Demasoni as a pet if you are willing to offer them for free or even better, you could sell them to other hobbyist to raise some cash to replenish your fish supplies or to simply upgrade your aquarium accessories. A fine juvenile specimen can easily fetch up to $10 or more per fish.
The aquarium which houses your pet should have plenty of decor made up of rocks to form large caves and passageways similar like the rocky environment in the wild which they come from so that the fish can hide inside it and feel secure. Sometimes it is better to use a small inverted flower pot instead if you have a difficulty arranging the pile of rocks together. Try to use sand as well as it will make things look more natural and if possible by any chance your local fish shops have some supply of live aquatic plants, you can try to add in one as well. Go for those types which have large leaves such as Anubias but please make sure that you have firmly tied the whole bunch together secured onto a piece of bogwood and then bury into the substrate, or else your enthusiastic cichlids will try and find a way to uproot and move things around as they want to. Plants also make a wonderful addition to the tank as your cichlids will spend their time nipping on the leaves and tearing away chucks of it if they get too hungry. The water which your pet fish live in should be slightly alkaline with pH in the range of 7 to 8 and also with hardness level of between 12 to 13 dGH. Don’t worry if you have problem understanding what all these terms mean because you can always get an aquarium water density meter to conduct the hardness test and to get to the correct ideal level suitable for your fish. You can also read up topics about water hardness with a table to help you understand better.
Just like any other freshwater tropical fish, Demasoni requires constant supply of clean water to thrive and as such routine aquarium maintenance should be periodically carried out. Most cichlid tank that I’ve seen employs the use of high-powered aquarium filter to ensure that the water is crystal clear at all times. That being said, water cleanliness should not be much of a concern because their diet are basically plant-based which means that those water-polluting foods stuff with animal origin like shrimps, fish meal and worms are not needed at all. Your fish should readily accept algae sticks and if for any reason you to decide to use pellets just make sure that the main ingredient contains wheat germ as special meal. There are a few commercially prepared aquarium foods with top brand names like Hikari and Tetra which you can try that I know are specially made for cichlids fish.