Tony Wu / Korean sandlance (Hypoptychus dybowskii) embryos developing inside eggs, on Sargassum, close up. Hokkaido, Japan. May.

Tony Wu / Korean sandlance (Hypoptychus dybowskii) egg clusters on Sargassum (Sargassum horneri). Fish produce sticky secretion in kidneys that adheres eggs to Sargassum. Hokkaido, Japan. May.

Tony Wu / Korean sandlace (Hypoptychus dybowskii) fish eggs freshly spawned and attached to Sargassum (Sargassum horneri) by a sticky secretion, Japan, Pacific Ocean.

Tony Wu / Korean sandlace (Hypoptychus dybowskii) male tending to fresh eggs which a female has deposited on Sargassum (Sargassum horneri), Japan, Pacific Ocean.

Tony Wu / Korean sandlace (Hypoptychus dybowskii) male tending to fresh eggs which multiple females have deposited on Sargassum (Sargassum horneri), Japan, Pacific Ocean.