Oxyeleotris caeca

Three specimens are held by the Western Australian Museum, two females and one male. The three specimens range from 82.6 to 92.3 millimetres (3.25 to 3.63 in) long, with a spine consisting of 28 vertebrae. The species has lost pigmentation in many areas, although not on its upper body. Its vestigial eyes are not externally visible, although some pigmentation remains where the eyes would be. Other members of the Oxyeleotris genus are known to be able to breathe air.

The karst limestones of the island of New Guinea create fragmented ecosystems with unique local conditions, likely facilitating speciation. O. caeca was discovered at 6°34.5′S 143°29.5′E near a village called Kafa/Kafka, in a creek which fed into the Mubi River, itself a tributary of the Kikori River. The location where the fish were collected was 100–200 metres (330–660 ft) downstream of a cave from which the creek flowed out. While it likely originated from the local karst cave system, it is frequently caught in surface waters during the wet season. In surface waters, the species is often found under stones, and is captured by placing a net slightly downstream of a stone before turning that stone over. It is not known how extensive the underground cave system is, but it is thought to be large. The karst landscape where the fish was found covers around 15,000 square kilometres (5,800 sq mi), making it the largest contiguous karst area in the country. From the location where O. caeca specimens were found, the karst landscape reaches Lake Kutubu, which is 15 kilometres (9.3 mi) northwest. There is some oil and gas drilling in this area. The creek where the holotype was caught was about 650 metres (2,130 ft) above sea level.