This study aims to get the best stocking density of Climbing perch reared with a recirculation system using taiwanese mackerel biofilters. The method used was a 1-factor Completely Randomized Design (CRD) experiment, 5 levels of treatment and 3 replications, so that the experiment set amounted to 15 units. The treatments were P1 (48 fish/80 L), P2 (52 fish/80 L), P3 (56 fish/80 L), P4 (60 fish/…