The experiment was done to assess the ability of decreasing nitrogen and phosphorus from mangrove leaves via heterotrophic bacteria. The experiment was arranged by a randomized complete block design. R. apiculata leaves were incubated in brackish water at salinities of 5 and 10 ppt. There were 3 treatments with 3 replicates: (1) without nitrogen supplement-without leaves; (2) nitrogen supplement-without leaf; (3) nitrogen supplement-with leaf. The results showed that total nitrogen concentration from water decreased lightly in range of 1.12 ? 2.19 mg/L at the treatment of nitrogen supplement-without leaves; whereas the treatment of nitrogen supplement-with leaves significantly decreased in comparasion the treatment without leaves (0.9-5.1 mg/L). The ability of nitrogen reduction by heterotrophic micro-organism that attatched on R. apiculata leaves was reached approximately 45%, 25%  and 9% in the first, second, third weeks respectively. Total nitrogen could be reduced 0.029mg/day/g DW.