Fig. 4

Spearman’s correlation and redundancy analysis of pangasius and tilapia pond water. Correlation analyses were carried out between bacterial alpha diversity (Shannon) and salinity, temperature, pH and DO using Spearman’s correlation (linear regression model) for pangasius ponds (A-D) and tilapia ponds (F-I). Redundancy analysis (RDA) presented shows the correlation among samples (fish species), environmental factors and bacterial families in Pangasius pond (E) and Tilapia pond (J). Black arrows show vectors of the significant microbes at family levels while red arrow shows vectors of the environmental factors. A positive correlation is indicated when the angle between vectors is less than 90°, while a negative correlation is indicated when it is greater than 90°. Any vector perpendicular to each other indicated no correlation