African Cichlid Fishes

Over 2,000 species of freshwater fish across African lakes representing the fastest known vertebrate radiation. Lake Victoria alone hosts 500+ species that arose from a single ancestor in approximately 15,000 years. Species occupy distinct niches defined by depth, diet (algae scrapers, scale-eaters, snail-crushers, fish predators), and microhabitat.

Cichlids' extraordinary radiation is attributed to pharyngeal jaws (a second set of jaws in the throat allowing independent specialization), ecological stratification by depth, and color-based mate choice enabling sympatric speciation. Their diversity demonstrates how modularity enhances evolvability.