2A slim, brightly coloured Indo-Pacific fish, Gonorhynchus gonorhynchus (family Gonorhynchidae), which burrows in sand on the seabed; also called beaked salmon, rat-fish.
Origin
Early 19th century.
Definition of mousefish in US English:
mousefish
noun
1The sargassum fish, Histrio histrio.
2A slim, brightly coloured Indo-Pacific fish, Gonorhynchus gonorhynchus (family Gonorhynchidae), which burrows in sand on the seabed; also called beaked salmon, rat-fish.