High in nutrients, green mussel Perna viridis can be used for fish meal replacement in fish diet, yet they contain heavy metals. The addition of Humic Acid (HA) in animals feed brings many advantages, one of which it can chelate heavy metals. HA addition in feed formulation is needed to prevent the accumulation of heavy metals in fish body. An experiment was designed to evaluate the response of HA addition in the diets made of green mussels which contains heavy metals on the growth performance and feed efficiency of Asian seabass, Lates calcarifer juveniles. The experiment was designed by Completely Random Design (CRD) with 5 treatments and 3 replications. A total of five experimental diets were formulated with difference dosage of HA addition (0, 400, 800, 1200, and 1600) mg Kg-1 of feed in the experimental diets (A, B, C, D and E), respectively. The experimental diets were fed to triplicate group of 15 Asian seabass juveniles with initial body weight of 4.30 ± 0.60 g in a 70 days cultivation by feeding at satiation. The result shows feed comsumption, feed digestibility, protein retention, growth performance and feed eficiency were significantly affected by the HA addition in the fish diet (P< 0.05). Treatment E with HA addition 1600 mg Kg-1 diet proved to give best biological response among all treatments. This indicates that the humic acid addition in the diet formulation can improve the utilization of feed for fish growth. The heavy metal Cd in flesh of Asian seabass is still under the limit set in the food safety standard, so the fish in this experiment are still considered safe for human consumption. The present study concluded that green mussel meal as alternative source protein with HA addition can be considered as potential feed additive for the diets of Asian seabass juveniles.