Channichthys mithridatis attains a maximumtotal length of. The first dorsal fin has spines and there are 32-34 dorsal fin rays while the anal fin contains 30-32 soft rays. The overall colour of the body and head varies from light green to dark olive with the crown of the head being rather darker than the body. There are 3-4 darker cross bars, two of which are underneath the second dorsal fin, and are present on the body of some individuals. The lower part of the head and body are white. There are clear silver-white spots at the bases of the pectoral fins and between the pelvic fins. Males are darker than females.