African Cichlids - How do they Communicate? - I
by George J. Reclos
THIS ARTICLE APPEARED IN FAMA MAGAZINE IN AUGUST 2002
It is well known among hobbyists keeping African Rift Lake cichlids that those species are generally characterized by aggression, territorial behavior (which can be directed against conspecifics or other species) and a special parental care (mouthbrooding). What most of us are puzzled and attracted by is the behavior of those species in captivity. Very often we refer to these fishes as “fishes with personality”. However, most hobbyists, when they search for more information about those species, they realize that the fish they keep do not behave as they do in their natural habitat – not entirely anyway. Thus, species known to be mildly aggressive in nature (e.g. Melanochromis chipokae) become killing machines in the confinements of an aquarium. Furthermore, the same species behaves differently in tanks with different decoration and size or in the presence of different tankmates. Another example which emphasizes this difference is the high degree of hybridization for certain species which, even if it happens in their natural habitat, is far rarer.
While it is very easy to understand why a specific species will behave differently in a bigger or more suitably aquascaped tank, it is very difficult to understand why it will behave differently in the presence (or absence) of another species in the same tank. What’s more, we can even see things that would never take place in the wild, such as a grown up mbuna terrorizing a half grown hap which in nature is its natural predator. We also know that fish added last find it more difficult to adapt and claim a high place in the existing hierarchy while that same fish could be the hyperdominant fish in another setup. Moreover, I have observed that the behavior of cichlids changes dramatically according to other parameters, most notably the lighting conditions. Thus, my 25 cm male Cyrtocara moorii will be the hyperdominant fish in the tank when the tank’s lights are off and there is little ambient light while it will be severely harassed by the male Placidochromis electra when the lights go on. I have also noticed that - because of the extremely stable photo period in my tanks - the fish slow down and become far less aggressive shortly before the lights are scheduled to by turned off. Those are observations made by many cichlid lovers but most of us simply rely on the “personality” issue when we need an explanation.
What is it then that cichlids recognize on other cichlids ? How do they know if there is a female of the same species, if their natural predator is in the same tank or which is the best male to spawn with ? How do males decide which is going to be the dominant one? Why do they fight ? Why do Aulonocara species readily cross breed in captivity and not in the wild ?
It has been postulated that African Rift Lake cichlids rely on vision - and especially colors and shape - to communicate with other cichlids. Of course the term “colors” need to be explained further. Cichlids have colors, we all know that, but the colors they have are the result of a long evolution. These colors are the optimal colors for the environment of any given cichlid species since they allow it to be recognized by the females while at the same time, too bright or unsuitable color morphs are taken care by the predators. This could be the reason why some cichlids show a great geographic variation while others not – colors matching one specific habitat, might be undesired in another. The colors preferred in shallow clear waters are the vivid ones while the colors preferred in deep waters are the pale one – where blue is the most common hue.
This clearly explains why the mbuna of Lake Malawi or the rock fish of Lake Victoria are vividly colored as they live in relatively shallow waters. It also explains why the female mbuna are also vividly colored as opposed to the females of the haps. Since the haps live in the open and usually deeper water, vivid colors are not the best option. There are two reasons for that. Firstly, most of them are predators so vivid colors would be a handicap when chasing their food near the water surface (where those colors would warn their pray while at the same time the predator will become a pray to birds). Secondly, at greater depths the light is limited so only highly contrasting colors could be visible. This is the reason haps rely far more on their melanin patters and shape for recognition while the females usually have a neutral silvery or brown/beige coloration. It is the melanin patterns that matter, not the color.
This is further demonstrated by the behavior of cichlids as we see it in our tanks. We all know that haps will “play” with their bars, dots or blotches while this is not often seen with mbuna (some mbuna species will never change their color). We also know that cichlids showing similar melanin patterns may fight even if they belong to different species and this is especially so between haps (e.g. Buccochromis and Mylochromis spp sharing the same diagonal black stripe).
Female Buccochromis lepturus
Female Mylochromis sp (possibly M. Sphaerodon).
It has also been shown that the combination of color, melanin pattern, shape and size is what is the key factor which makes one cichlid the dominant one in a tank. Those elements are also what taxonomists use for the correct classification of the species.
Recognition is vital for cichlids in two very important aspects of their lives. Competition for food and breeding. Aggression and territorial behavior is the natural consequence since the cichlid must protect its food and breed.
As we know cichlids from the African Rift Lakes have evolved extremely specialized diets and jaws. Thus, while many species will feed on the auchwuchs on the rocks, competition is less fierce since, due to their specialization, they are only able to consume a special portion of the available food sources1. It is obvious that a cichlid able to eat food found inside small crevices doesn’t compete directly with an algae grazer which will only feed on the algae in the flat part of the same rock. When these two species come in close range, their colors and shapes make them recognizable and each one will tolerate the presence of the other. It goes without saying that the female of any given species is regarded as a food competitor if not in breeding conditions. Thus the male will tolerate the females for a short period of time but definitely not after breeding. This also explains why some female mbuna show aggression to other females of the same species. Food is a vital aspect of a cichlid’s life and we should always keep in mind that their natural habitat is usually oligotrophic.
Of course, food is always offered in excess in the confinements of our tanks. So this should not be a reason for fights and this is sometimes the case. However, in most cases, the aggression, which is built in the cichlids, will prevail even if there is no reason for it.
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