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How have cave-dwelling ostariophysans adapted to darkness?

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knifefish — ostariophysan Knifefish, or featherback (Xenomystus nigri)

Cave-dwelling ostariophysans have undergone convergent evolution to adapt to life in environments characterized by near-total darkness. These evolutionary trends primarily involve the reduction or complete loss of eyes and the loss of body pigment.1

To compensate for the loss of sight, these fishes have developed specialized sensory systems. Most notably, there is a significant development of certain sense organs, particularly the lateral line system, which allows them to navigate and interact with their surroundings in the absence of light.1

Examples of ostariophysans that have adapted to these subterranean habitats include:
* Various species of cyprinids found in Africa, the Middle East, and Java.1
* The characin Astyanax jordani (also known as Astyanax mexicanus) in Mexico.12
* Ictalurid catfishes in the United States and Mexico.1
* Several genera of pimelodids and trichomycterids in South America, as well as clariids in Africa.1