Cichlid
Cichlids /ˈsɪklɨd/ are fish from the family Cichlidae in the order Perciformes. Cichlids are members of a group known as the Labroidei, along with the wrasses (Labridae), damselfishes (Pomacentridae), and surfperches (Embiotocidae). This family is both large and diverse. At least 1,650 species have been scientifically described, making it one of the largest vertebrate families. New species are discovered annually, and many species remain undescribed. The actual number of species is therefore unknown, with estimates varying between 2,000 and 3,000. Cichlids are among the most popular freshwater fish kept in the home aquarium.
Description
Cichlids span a wide range of body sizes, from species as small as 2.5 centimeters (0.98 in) in length (e.g., female Neolamprologus multifasciatus) to much larger species approaching 1 meter (3.3 ft) in length (e.g. Boulengerochromis and Cichla). As a group, cichlids exhibit a similar diversity of body shapes, ranging from strongly laterally compressed species (such as Altolamprologus, Pterophyllum, and Symphysodon) to species that are cylindrical and highly elongate (such as Julidochromis, Teleogramma, Teleocichla, Crenicichla, and Gobiocichla). Generally, however, cichlids tend to be of medium size, ovate in shape and slightly laterally compressed, and generally similar to the North American sunfishes in morphology, behavior, and ecology.
Many cichlids, particularly tilapia, are important food fishes, while others are valued game fish (e.g. Cichla species). The family also includes many familiar aquarium fish, including the angelfish, oscars, and discus. Cichlids have the largest number of endangered species among vertebrate families, most in the haplochromine group. Cichlids are particularly well known for having evolved rapidly into a large number of closely related but morphologically diverse species within large lakes, particularly Tanganyika, Victoria, Malawi, and Edward. Their diversity in the African Great Lakes is important for the study of speciation in evolution.[10] Many cichlids that have been introduced into waters outside of their natural range have become nuisances, such as tilapia in the southern United States.
慈鲷科（Cichlidae）又称丽鱼科、丽鲷科，有84属680种。分布于南美洲、非洲、东南亚和南亚热带海域或淡水中。体高而短，被栉鳞，侧线中断。杂食性。分布于热带海水或淡水中。现被我国作为养殖对象之一的非洲鲫鱼亦称“尼罗罗非鱼”体形似鲫，呈暗褐色；背鳍鳍棘发达，臀鳍有三棘，尾鳍截形，侧线中断。有特殊产卵习性，生殖季节，雄鱼寻找适宜做巢的地方，用嘴挖出一个圆坑，雌鱼在坑内产卵，并随即吞到口中，这时雄鱼排精，精液也被雌鱼吸入口中，卵子在口中受精、孵化，孵出的小鱼仍留在母鱼的口中，直到小鱼卵黄囊消失才离开母口，如遇敌害，母鱼张口让小鱼进入口内，并驱赶敌害。原产热带非洲，现已广泛移入东南亚，中国从越南引入，南方各地广泛养殖，近来已辟为工厂化养殖对象。很多种类体色艳丽，是常见热带淡水观赏鱼。罗非鱼（Tilapia）原产于非洲，现已作为食用鱼引入我国并广泛饲养。
