Cichlid Origins: Why Are Cichlids So Cool?
Posted on November 05 2018
African Cichlids are undoubtedly one of the most various, fascinating, and beautiful types of fish, but how did they get to be so? Where do they come from, and what are the interesting paths of evolution which molded them into such amazing creatures? Today, we’re going to learn about where cichlids come from, and how the forces of evolution created them to be so colorful, behaviorally diverse, and filled with such personality.
Although the most popular cichlids are from the three African lakes Malawi, Tanganyika, and Victoria, cichlids have also been found in many other parts of the world, almost entirely in tropical regions. This is of course because the various types of cichlids from different geographical regions have common, not-so-distant ancestors which swam in the oceans. Some other places that cichlids have been found are Central and South America, Madagascar, Cuba, and even the Middle East.
Cichlid morphology (body shape) varies greatly, from 1 inch to 3 feet in estimated 2-3,000 different species, only some of which are officially identified. While most have a relatively typical “fish” shape, many are also elongated, vertically compressed, or even triangular. They are actually extremely successful from an evolutionary point of view, and represent one of the largest family of vertebrates. What ties all species of cichlids together is a specific jaw structure they all share, which essentially allows them to have two jaws. Cichlid diversity is actually not a very old phenomenon, having mostly emerged relatively recent, on the evolutionary timescale.
They are also very interesting from a zoological or behavioral perspective, with a variety of temperaments and survival strategies. For instance, many cichlids are extremely territorial and aggressive, and cannot exist with many, or in some cases any other fish in their aquarium, while others are more placid. When it comes to mating, they either fall into the monogamous or polygamous categories, and there are no known cichlids who engage in male-only parental care to their offspring, which is the norm in most fish species. In the case of the polygamous cichlids, the females are essentially the sole caretakers.
Origins of Diverse Traits
The origin of African Cichlids is traced to the Nile River, where at some point around 40 million years ago, the river overflowed and these freshwater fish spilled over into the three lakes. The rest is evolutionary history, as the various divergent paths of adaptation taken by these many species created the plethora of cichlid species we see today. Every unique trait was, of course, a way to adapt to the environmental conditions of their new homes, the predators therein, and the various conditions present.
The three great lakes in which we find cichlids are diverse environments, and as they spread throughout the lakes, they developed a variety of adaptive traits, for various reasons.The myriad fascinating evolutionary developments are too many to encompass in the span of this post, but I will share just a few, to give you a glimpse of the fascinating world of cichlid development over the eons.
Some cichlid species developed the ability to carry their fertilized eggs in their mouths until they hatched, for instance, because they had to adapt to breed in waters too turbulent for normal methods of depositing in rocks or sand on the lake’s floor. Other’s adapted to be able to eat the scales of other fish, or small creatures with shells such as crabs. Another fascinating behavior of some cichlids is bower-building, or what some may know as sandcastle building by the males of some species of cichlid. This seems to be for the purpose of attracting mates, but why mates would be attracted to these bowers is still a bit of a mystery.
The origins of cichlid traits are something which biologists still theorize about, and there is not complete consensus in every case, but still many likely hypotheses. For instance, much of the color variation may be due to the fact that males with more varied colors are attacked less by other males, perhaps because they are not recognized as the same species. Other factors influencing coloration may be due to the limited abilities of the species to perceive colors within a certain range.
Whatever the reasons and explanations for all of the beautiful varieties of cichlids we now have, we can all have a testament to the glories of evolution in our own aquarium, and that is something we are perpetually thankful for.