Snakehead (Channa argus) is a commercially important freshwater fish cultured in China. The induction of triploidy can be used to control unwanted reproduction in culture and is an important breeding method in fish. Given this, the development of triploid stock would be of significant benefit for aquaculture. In the present study, the second polar body extrusion was inhibited by heat shock for triploidy induction in the Snakehead, and the optimal induction conditions were evaluated. Ploidy of putative triploid larvae was determined by means of DNA content and red blood cell size identification method. Meanwhile, the growth performance of triploids and diploids were compared. All the data were analyzed by using Microsoft excel 2003 and SPSS 13.0. The results showed that: (1) the highest triploid induction rate of 87.69% was observed when the fertilized eggs were shocked at 42℃ for 3min after fertilization 4 min, and incubated at water temperature of (28 ± 0.5)℃ (Table 3); (2) the cellular DNA content of triploid Snakehead was 1.50 times to that of the diploid (P < 0.01); (3) there were very significant differences in cell and nuclear sizes between the triploid and diploid erythrocytes (P < 0.01) (Fig. 2), and the erythrocyte volume and nucleus volume of triploids were 1.69 and 1.60 times of the diploids, respectively (Table 5); (4) from 4 to 8 months of age, the triploids growth rates (body length, weight) were not significantly different compared to the diploid controls (P > 0.05) (Table 6). In conclusion, this technique lays foundation and provides important tool for polyploid breeding in Snakehead.