The family of cichlids or Cichlidae is a very large family. Currently, about 1650 species have been described, but many more species are already known. some 1400 species are still awaiting official description and new species are still being discovered every year. They fall under the suborder Labroidei along with Labridae, Pomacentridae and Embiotocidae, all seawater fish.
All cichlids have at least one thing in common. They have a second set of jaws (pharyngeal jaws). These jaws are not visible from the outside. Most fish suck in their food, cichlids are helped by these throat jaws to get the food to their stomachs. The muscles of these pharyngeal jaws can transport the food from the front of the mouth to the back or even help to grind the food as in the snail-eating cichlids.
In addition to these pharyngeal jaws, they are further distinguished from the rest of the suborder Labroidei by:
A single olfactory groove hole on either side of the head.
The lack of bone structure under the eye.
A divided lateral line in two parts, one on the upper half of the flank and a second across the middle of the flank from roughly half the body to the caudal peduncle (except in Teleogramma and Gobiocichla).
A peculiarly shaped otolith (part of the inner ear).
The stomach opens into the small intestine on the left side instead of on the right side as in the other families of the Labroidei.
The division into genera and species is far from complete for the Cichlid family and of course also problematic in some cases. There are regular shifts within different genera because the scholars do not always agree with each other.
Nine sub-families are recognized within the Cichlid family: Astronotinae, Cichlasomatinae, Cichlinae, Etroplinae, Geophaginae, Heterochromidinae, Pseudocrenilabrinae, Retroculinae and Ptychochrominae
Distribution and Habitat
Cichlids originate from the primeval continent of Gondwana, about 160 million years ago this primeval continent began to fall apart and Africa, South America, Madagascar, and India were created, these are still the locations where Cichlids are most common. They can now also be found in Central America up to the Rio Grande.
Cichlids mainly inhabit fresh water and to a lesser extent brackish and salt water. However, there are exceptions of a number of species that can withstand brackish water for a longer period of time, such as a number of Etroplus and Sarotherodon species. However, Alcolapia and Danakilia take the cake, they inhabit Lake Abaeded in Eritrea, a saltwater lake with a salinity of about 14.5 grams/liter, a temperature of 29 to 45 degrees, and a conductivity of around 29,000 micro siemens (freshwater somewhere between 200 and 2000 micro siemens).
Due to the long history and size of this family, it should come as no surprise that the cichlid family shows various forms of breeding behavior. Some forms of breeding behavior are characteristic of the environment, but may also have originated elsewhere. For example, if we look at the hatching of the eggs in the mouth of the female, this occurs in almost all Malawi cichlids.
The different forms they have are:
Substrate brooders – the eggs are stuck to a piece of stone, leaf or other substrate.
Mouth brooders – the eggs are incubated in the mouth by the female (or male).
Larvophilous Mouthbrooders – the eggs are laid in the open or in a hole and hatched. The larvae are then taken up in the mouth to continue growing.
Cave brooders – the eggs are hatched in a cave.
In some cichlid species, parental care ceases after the eggs hatch. Many other species, however, have longer aftercare from the parents. For example, they are regularly taken back into the mouth to protect against predators. Other species move the newly hatched larvae from pit to pit in search of microscopic food.
The Cichlid family is not only very large but also very diverse. The size, shape, color, breeding, and behavior have a very wide range of possibilities. This also makes cichlids very interesting to keep in the aquarium. Whether you like big, small, aggressive, or peaceful: there is something for everyone.