Which Lake Baikal fish is nearly transparent and gives birth to live young?

The Baikal oilfish is the nearly transparent Lake Baikal fish that gives birth to live young.

Baikal oilfish, also called golomyankas, are translucent sculpin-like fish found only in Lake Baikal, Russia. The name covers two species in the genus Comephorus: the big Baikal oilfish and the little Baikal oilfish.

Unlike most fish, female Baikal oilfish are viviparous rather than egg-laying. They give birth to roughly 2,000–3,000 larvae, and many females die after reproduction. Their translucent bodies, lack of scales, porous bones and oil-rich tissues help them remain buoyant in the lake’s deep open water.

The oilfish is not the same as the commercially familiar omul. Omul is an endemic whitefish and an important local food fish, while Baikal oilfish are a major prey item for the Baikal seal. They are also among the deepest-living freshwater fish known.