This study aimed to investigate the effects of heat-killed Lactobacillus plantarum L-137 (HK L-137) on the growth, survival, intestinal morphology, immune response, and disease resistance of snakehead (Channa striata). The fish (7.30±0.07 g) were fed diets supplemented with 0 (control), 2, 4, 10, 20, and 40 mg of HK L-137 kg-1 of feed. After feeding (60 days), the fish were injected with Aeromonas hydrophila and the cumulative mortality was recorded for 14 days. The results showed that the dietary administration of HK L-137 did not affect the water quality parameters, including water temperature, pH, dissolved oxygen, total ammonia nitrogen, and N-NO2. HK L-137 supplemented diets significantly improved the growth, protein efficiency ratio, apparent digestibility coefficient, feed conversion ratio, and survival rate of fish. HK L-137 supplemented diets significantly increased the white blood cell count and lysozyme activity, but did not affect the red blood cell count. The height and length of the intestinal villi and the crypt length of the intestine of fish fed HK L-137 were significantly higher than those fed the control diet. The cumulative mortality of fish fed HK L-137 (at 2, 4, 10, 20, and 40 mg kg-1 feed) was significantly lower than that of control fish after challenging with A. hydrophila. Among the levels of HK L-137, 2 mg HK L-137 kg-1 feed showed the lowest cumulative mortality of the fish (6.66%), not significantly different from that of the negative control (3.33%). Altogether, HK L-137 conferred beneficial effects to snakehead.