Aims To describe the biofilm microbiota associated with various feeding phases during larval common dentex (Dentex dentex) culture. Methods and Results A targeted metagenomic (metagenetic) study was performed by means of 16S rRNA gene-based PCR and NextGen pyrosequencing. The resulting dataset was scrutinized with microbial community analysis software (r packages) using r/Rstudio. While median observed and estimated alpha-diversities were 171 +/- 38 and 207 +/- 27 taxa, respectively, 72 center dot 1-85 center dot 8% of individual biofilm communities comprised only 27-46 taxa. Members of the genus Methylobacterium and family Rhodobacteraceae dominated biofilms formed during all feeding phases while genera Nannochloropsis and Tetraselmis microalgae were major constituents of biofilms during rotifer live feeding. Both potential fish pathogenic genera, for example, Vibrio and putatively probiotic taxa, for example, Phaeobacter gallaeciensis were identified. Conclusions Relatively stable biofilm communities were identified during each feeding phase but varied significantly between feeding phases, most likely in response to the introduction of live feed/microalgae-associated bacteria into rearing tanks. Significance and Impact of the Study The structure of the bacterial communities identified represents a 'template' for successful larval dentex culture and provides a foundation for future investigations into failed production cycles.