N – 1 9 ° N . ▁It ▁has ▁been ▁found ▁in ▁the ▁waters ▁near ▁Hong ▁Kong . ▁Gener ally ▁they ▁inhab it ▁the ▁ep ip el ag ic ▁layer ▁to ▁ 3 7 0 ▁m ▁( 1 2 1 3 ▁ft ). ▁Ad ult s ▁are ▁mainly ▁bottom - d well ing ▁but ▁migr ate ▁up ward ▁at ▁night ▁in ▁search ▁of ▁food . ▁ ▁The ▁Japanese ▁but ter fish ▁has ▁a ▁com pressed ▁body , ▁somewhat ▁o val - sh aped , ▁and ▁is ▁wh it ish ▁to ▁gray ish ▁in ▁colour ; ▁in ▁the ▁young ▁fish , ▁the ▁colour ▁is ▁dark er : ▁a ▁pale ▁brown ▁or ▁black ish ▁brown . ▁Some ▁other ▁features ▁of ▁this ▁fish ▁are ▁a ▁robust ▁sn out , ▁a ▁relatively ▁small ▁mouth , ▁and ▁the ▁upper ▁j aw ▁extending ▁to ▁below ▁anterior ▁margin ▁of ▁eye . ▁The ▁fish ' s ▁teeth ▁are ▁small , ▁con ical , ▁and ▁in cis or - like . ▁Sp ines ▁of ▁the ▁Japanese ▁but ter fish ' s ▁d ors al ▁fin ▁are ▁short ▁and ▁not ▁separated ▁from ▁the ▁soft - rayed ▁portion . ▁The ▁scales ▁on ▁the ▁body ▁of ▁the ▁but ter fish ▁are ▁small , ▁cy clo id , ▁and ▁very ▁decid uous ▁( mean ing ▁that ▁they ▁are ▁shed ▁off ▁easily ). ▁ ▁This ▁species ▁is ▁of ▁economic ▁importance , ▁commer cially ▁sought ▁after , ▁and ▁caught ▁by ▁tra w l ▁by ▁Japanese ▁and ▁Taiwan ese ▁fish erm en . ▁The ▁total ▁catch ▁reported ▁for ▁this