Aggresiveness
In general cichlid species are known to be aggressive. But they are also good at taking aggression. So it is okay to have some healthy aggression in a cichlid tank - it is part of their nature. But this aggression should not cause some fish to hide all the time in a hidden corner and eventually get weaker and die. One of the ways to avoid this in a cichlid tank is a technique known as overcrowding. If you have more fish than normal, the aggression is likely to be scattered resulting in less severe aggression (and stress) over any single fish.
Also, most tanks will have a dominant fish which we may fittingly call as the "boss". In my tank, the boss is one of the male mpangas. He usually gets what he wants in the tank, but he is not extremely aggressive. I would say that the second boss is a male pindani. He could even become the first boss if he was as large as the mpanga. We will see what happens as they grow up. After the mpanga and the pindani, a larger male electric yellow could be considered as the third boss. He is even sometimes not intimidated by the challenges of the second boss. They sometimes fight tooth to tooth with no clear winner.
I also have several demasoni, allegedly one male and two females according to the seller that I bought them from. However, it is hard to tell apart their gender especially when they are juveniles. The females are smaller but I'm not sure if is because of their gender or age. In my tank, the females don't really mess with anybody and the male sometimes makes mock fights with the electric yellow and the pindani. But nothing serious really.
I also have several demasoni, allegedly one male and two females according to the seller that I bought them from. However, it is hard to tell apart their gender especially when they are juveniles. The females are smaller but I'm not sure if is because of their gender or age. In my tank, the females don't really mess with anybody and the male sometimes makes mock fights with the electric yellow and the pindani. But nothing serious really.
Among the other fish that I have, yellow tail acei, firefish, and the ahli are really not aggressive at all (ahli being the least aggressive). Even when they behave aggressive it is only toward their own species (and in the form of chasing females). The convict cichlids, being two smaller females, are also not aggressive. However, they are very sturdy and not stressed at all by the larger and different species around them. They sometimes chase each other though.
In summary, based on my experience, I believe that I have a pretty balanced tank. There is some chasing around but nothing deadly. I must add, however, that at one point I had a male auratus in my tank. That guy chased most other fish around until they were too scared to come out even for feeding. So I returned that fish to the local fish store, and I believe that was a good decision. So for anyone who wants to keep an auratus, please make sure that you have a very large tank, and compatible fish that can deal with high levels of aggression.
In summary, based on my experience, I believe that I have a pretty balanced tank. There is some chasing around but nothing deadly. I must add, however, that at one point I had a male auratus in my tank. That guy chased most other fish around until they were too scared to come out even for feeding. So I returned that fish to the local fish store, and I believe that was a good decision. So for anyone who wants to keep an auratus, please make sure that you have a very large tank, and compatible fish that can deal with high levels of aggression.
Feeding
I must start by saying that cichlid will eat most anything that you throw at them, like most fish would do. However, you have to be careful about what and how much you feed them, as otherwise they may die due to bloating. See this excellent article on the topic. The fish that I have in my tank have a mixed bag of diets. Pindani, mpanga, acei, and demasoni are all herbivores. Electric yellow and convict are omnivores, and firefish and ahli are carnivores. So at one point I was concerned about how to feed them appropriately. Later as I was watching a youtube video I learned about this awesome brand of food called the New Life Spectrum. I tried it and I loved it. The food is very well-balanced to satisfy the nutritional requirements of different types of cichlids. It simply looks and feels high quality. The best of all, it does not quickly dissolve in the water ensuring water clarity. I usually feed my fish once a day (mornings) about a teaspoonfull of this food. Also, I usually let them fast once a week, which I believe helps their digestive systems to clean up any residual waste.
Besides devouring their meals, different types of cichlid enjoy different kinds of snacks throughout the aquarium. Yellow tail acei are the best algae eaters. They literally try to scrape off the algae that grows on the rocks and on the aquarium glass. Pindani, on the other hand, prefer my plants. Although I have cichlid proof (well, sort of) plants such as Anubias and Java Fern, pindani still eat them slowly but steadily. Especially when the new leaves are fresh and tender, they make the most damage so the leaves never grow up to their full potential. They manage to eat fully grown up leaves as well.
Mating
The last thing I will discuss in this post will be the mating behavior of my fish. After every cleaning up of the aquarium, most males will pick some spots around the rocks and dig up the sand to make nests. They will then try to attract females by shaking violently in front of them. If the breeding happens, the females hold the fertilized eggs in their mouth for about three weeks, until the babies hatch and are old enough to swim on their own. They eat almost nothing during this period, which in my opinion, is a miracle. They usually get weaker during this period though. I actually had a pindani female, who died soon after giving birth to her fry due to getting to weak to survive. The male aggression toward the female also makes things worse during this period. But in any case, if the female was strong enough to begin with, she will usually get back to her original form after releasing the fry.
As for the fry, I did not have a survivor yet who was born in the main tank. The adult cichlid are too fast for a new born baby. Also, while some cichlids do care for the young, I haven't seen this happening in my tank yet. They eat their own fry as well (so much for parenthood). You can certainly separate the holding female to a special container to protect the babies, but this brings about the problem of what to do with them when they grow up. Because you will have around 20 - 40 extra fish to find room for, per pregnant female. Selling them could be an option but it is really not worth the effort unless you are breeding some really rare fish. So in general, I let the nature run its course. At some point, I believe some babies can survive as there are many caves and crevices in my tank. Most importantly, if my java ferns grow as big as I see in some pictures, they could be perfect hiding spots for the baby and young fish.
Male Electric Yellow
Male Fire Fish
Male Hap Ahli
Female Convict
Male Demasoni
Female Hap Ahli
Male Mpanga
Female Mpanga
Male Pindani
Male Yellow Tail Acei