What was the reason behind the extinction of 200 species of cichlid fishes in Lake Victoria?

Introduction of Nile perch

The extinction of around 200 species of cichlid fishes in Lake Victoria primarily resulted from the introduction of the Nile perch.

Alien species invasions: When alien species are introduced unintentionally or deliberately for whatever purpose, some of them turn invasive, and cause decline or extinction of indigenous species.

The introduction of the Nile perch, a predatory fish species, into Lake Victoria had significant ecological consequences. Nile perch were introduced to the lake as part of an effort to boost fishing industries. However, these predatory fish had a substantial impact on the ecosystem. They preyed upon and rapidly depleted many native species of cichlid fishes, leading to a drastic decline in their populations. The imbalance caused by the introduction of the Nile perch disrupted the natural food web and contributed significantly to the decline and extinction of numerous native cichlid species in Lake Victoria.The Nile perch introduced into Lake Victoria in east Africa led eventually to the extinction of an ecologically unique assemblage of more than 200 species of cichlid fish in the lake.