Eleutheronema tetradactylum has two dorsal fins the first has 9 spines and the second has 13-15 soft rays with 13 being the mean. The anal fin has 3 spines and 14-19 soft rays. The pectoral fins have 16-18 rays and there are 4 pectoral filaments. The upper sides of the head and body have a slight darkish silver tinge, lighting in the lower flanks. Both dorsal fins show a blackish anterior margin with the remaining parts of the fins translucent and slightly dusky. The membranes of the pectoral fins are vivid yellow in smaller individuals but in larger fish this becomes duskier. The pectoral filaments are white. The pelvic fins are white with a yellow front edge while the caudal fin is blackish with a yellowish base. This species can attain a maximum total length of 2 metres (6.6 ft), although 50 centimetres (20 in) is a more normal size.