This is a picture of an elephant fish embryo.
Elephant fish are cartilaginous fishes, and are distant cousins of sharks, skates and stingrays. The elephant fish lives in deep water off the coasts of Australia and New Zealand, but migrates annually into shallow coastal bays to lay their eggs. Dr Andrew Gillis studies the embryonic development of elephant fish, by collecting their eggs by SCUBA diving at their egg-laying grounds. Normally, an elephant fish embryo will live in their egg and feed off of their yolk supply for 7 to 10 months before hatching out as a completely self-sufficient juvenile. However, these embryos may also be cultured outside of their egg cases, as seen here. This allows researcher to observe and photograph the development and growth of this unusual fish.
(Credit: Andrew Gillis)