Sponges are a diverse group of aquatic animals with porous bodies that produce a vast array of natural products, some with important medicinal properties, but their porous body structure also provides ample habitat for symbiotic microorganisms, which can account for up to 35% of their total body weight. Previous studies looking at the unique natural products produced by sponges have rarely taken this close relationship into account, making the extent to which microorganisms actually produce them unclear. To fill this gap, a team of researchers identified the chemical compounds found in the tissues of six sponge species from the Great Barrier Reef and their symbiotic microbes. Several compounds with potential roles in competition and defense against intruding organisms and oxidative stress were specifically attributed to the microbial cells, while the compounds produced by the sponge tissues may provide nutrients to the symbiotic microorganisms and aid in sponge defense. These findings lend important insight into the different chemical compounds produced by host sponges and their symbiotic microbes and how the stable sponge-microbe relationship is maintained through chemical interactions.