The cladobranch Berghia stephanieae is able to incorporate photobionts of its food source Exaiptasia diaphana and keeps these photobionts active for up to 5 days. Although both species are well-studied model organisms in the realm of mollusc-dinoflagellate ecology, the microbiome and its contribution to the photosymbiosis of the slugs has long been overlooked. Here we present the first microbiome analysis of freshly fed B. stephanieae and its food source under different one-week starvation conditions (low light, high light and dark).