Blepsias bilobus has a deep, compressed body which is covered in papillae which enclose a small spine that is embedded in a bony plate in the skin. There are cirrhi on the chin. The first dorsal fin is smoothly rounded and is not notched. The second dorsal fin and the anal fin are large and are located opposite each other. There are 8 or 9 spines in the dorsal finand 21 or 22 soft rays while the anal fin has 18 to 20softrays. The pectoral fin contains between 15 and 17 rays and the small pelvic fin has 3 soft rays. The caudal fin is rounded. The color is brown to olive-green on the upper body with indistinct blotches on the back, paler ventrally. The fins have dusky blotches except forthe darkbarredpectoral fin. The maximum published standard length is.