Previous studies have described the isolation of cellulolytic bacteria from the GI tracts and faeces of Panaque demonstrating the presence of a consortium of microorganisms performing cellulose breakdown ,. Using 16S rRNA and culture-based analyses, the enteric bacterial community of P. nigrolineatus appears distinct and specialised in each region of the GI tract. The dominant bacteria have 16S rRNA gene sequences similar to Proteobacteria, Firmicutes, Bacteriodetes and Actinobacteria ,,. The midgut contains phylotypes with high sequence similarity to cellulose degrading bacteria Clostridium, Cellulomonas, Bacteroides, Eubacterium and Aeromonas spp. as well as nitrogen-fixing Bradyrhizobium and Agrobacterium spp. that are capable of in situ nitrogen fixation . The hindgut is dominated by Bacteroidetes ,. Bacterial species richness has been shown to decrease distally from foregut, through to the midgut and hindgut. While the bacterial microbiota within the GI tracts of other fish have been studied –, comparatively little is known about the diversity, abundance, and role of the fungal microbiota in these systems . It is likely that fungi play an important role in the fish microbiome, yeasts have been identified as part of the normal microbiota of fish GI tract – and have been studied with specific relevance for fish health and yields in aquaculture.