Certain sponge species are difficult to identify using classical taxonomic characters, and other techniques are often necessary. Here we used 454-pyrosequencing of the 16S rRNA gene to investigate bacterial and archaeal communities of two distinct Cinachyrella morphospecies collected from two Indonesian marine lakes with differing degrees of connection to the surrounding sea. Our main goal was to assess whether these morphospecies hosted distinct bacterial and archaeal communities and to what extent these differed from those found in lake water. A recently developed bioinformatic tool (PICRUSt) was used to predict metagenomic gene content of the studied communities. Compositionally, sponge samples clustered according to morphospecies as opposed to marine lake indicating that each morphospecies hosted distinct bacterial and archaeal communities. There were, however, also differences in higher taxon abundance among lakes. In the less connected lake, for example, both Cinachyrella morphospecies had higher levels of the order Synechococcales. With respect to metabolic gene content, although there were pronounced differences in predicted enrichment between both morphospecies, both were putatively enriched for KOs involved in pathways related to stress response, energy metabolism, environmental information processing and the production of secondary metabolites compared to prokaryote communities in water. These morphospecies may thus prove to be interesting sources of novel compounds of potential pharmaceutical and/or biotechnological importance.