Why do cave fishes have reduced eyes?

Cave fishes, including certain members of the superorder Paracanthopterygii such as the percopsiforms, have evolved reduced, nonfunctional eyes as an adaptation to living in environments characterized by total darkness, such as limestone caves.12

Because these habitats lack light, vision is not a viable sensory strategy. In response to these conditions, cave fishes have developed elaborate systems of tactile organs distributed across their head, body, and tail. These sensitive organs enable the fish to navigate and detect their surroundings—including prey and obstacles—by touch, effectively replacing the need for sight. This evolutionary trend toward blindness and pale coloration is a common adaptation among various cave-dwelling fish species across different families, as they shift their reliance from visual cues to other sensory modalities suited for subterranean life.12