Oneiriodes dreamers are characterised by having spines on the sphenotic bone, a deep incision on the rear edge of the
operculum, and rod-shaped pelvic bones that are not expanded or expanded only slightly at the tips. The lobe of the
pectoral fin is short and wide with the length of the lobe being less than that of the longest pelvic fin rays. There is a spine on the
symphysis of the lower jaw and the lower margin of this symphysis is convex. The rays of the
caudal fin have no internal pigmentation and the black skin on the caudal peduncle does not extend past the base of the caudal fin. The
illicium merges from between the
frontal bones, the frontal bones are curved on their upper margin, and the subopercular bone is short and wide with a nearly circular lower part. There are 4, occasionally 5, soft rays in the
anal fin. A unique character of the metamorphosed females of
Oneirodes is that the posterior end of the
pterygiophore of the illicium emerges from the skin on the back, behind the head. The males have unpigmented skin between the nostrils, and the inner surface of the subopercle is also unpigmented. The caudal peduncle has no subdermal pigments, and there are between 7 and 13 denticles on the lower jaw. The females range in
standard length from , and the published species descriptions are based on females as there are no known morphological character that separate the males by species. The males are free-living and non-parasitic. Male specimens measure between . ==Distribution and habitat==