The cichlids are associated to the order of the Perciformes. Its natural habitat is found in South America, Asia, Africa and Europe. The known 900 species of cichlids are characterized exclusively by a dorsal fin of which has a hard spiny and soft spiny part. The length of the cichlids depend on the species and can vary between 3cm and 1m. Most cichlid species prefer temperatures of 22-30 ° C. The cichlids tend to be aggressive towards alien fish, it is recommended a welfare in a species tank. In Lake Tanganyika 350 different types of this popular aquarium fish are located.