I think it's about time we revive this thread.
This is the blind cave eel, Ophisternon candidum. Not a true eel, but rather more closely related to swamp eels. (Synbranchidae)
Collection project of all troglobitic fish species (those restricted to caves and subterranean habitats). [Primary Source](https://cavefishes.org.uk/checklist.php?type=cave) edit: Have additionally added the deepwater canyon-dwelling troglomorphic species from the lower Congo ([photos...