The effects of chronic elevated temperature on the skin and gut microbiota of juvenile zebrafish (Danio rerio)

The objective of this study was to examine and compare how chronic heat stress followed by cooling influences the skin and gut microbiota of juvenile zebrafish, using 16S rRNA amplicon sequencing. Bacterial communities were profiled on days 1, 30, and 60 across four treatment groups, two tissue types (skin and gut), and the surrounding tank water. We assessed characterised core and unique bacteriome members for each tissue, treatment, and timepoint, and identified differentially abundant taxa indicative of thermal stress responses. Our findings suggest that the skin microbiota may serve as a sensitive, non-invasive biomarker of fish health and recovery.