''Butis humeralis'', commonly known as the dark sleeper or olive flathead-gudgeon, is a fish native to the waters of Indonesia and

Indochina Mainland Southeast Asia, also known as the Indochinese Peninsula or Indochina, is the continental portion of Southeast Asia. It lies east of the Indian subcontinent and south of Mainland China and is bordered by the Indian Ocean to the west an ...

. Found in salt, brackish and fresh water, it reaches a

standard length Fish measurement is the measuring of individual fish and various parts of their anatomies. These data are used in many areas of ichthyology, including taxonomy and fisheries biology. Overall length * Standard length (SL) is the length of a fish m ...

of 14.2 cm. It closely resembles the crazy fish (''

Butis butis ''Butis butis'', the crazy fish, duckbill sleeper, or upside-down sleeper, is a species of sleeper goby that are native to brackish and freshwater coastal habitats of the Indian Ocean and the western Pacific Ocean from the African coast to the is ...

''), but is more solid in build and never has two black spots at the base of its pectoral fins.

References

Fish of Thailand Fish described in 1837 Fish of Indonesia humeralis {{Gobiiformes-stub