A juvenile pinnate spadefish.  It may use coloration similar to a bad-tasting

flatworm for protection.  The adult is very different -- a big silver fish with black bands.

(Laha, Ambon Island, Indonesia)

fish; spadefish; pinnate spadefish; juvenile; Chordata; Osteichthyes; Perciformes; Ephippidae; Platax pinnatus, South Pacific