A Unique Symbiosis in the Gut of Tropical Herbivorous Surgeonfish (Acanthuridae: Teleostei) from the Red Sea

Science  05 Jul 1985:
Vol. 229, Issue 4708, pp. 49-51
DOI: 10.1126/science.229.4708.49


Herbivorous surgeonfish (Acanthurus species) in the Red Sea harbor gut symbionts that include bacteria, trichomonadid flagellates, and a peculiar putative protist that attains densities of 20,000 to 100,000 cells per milliliter of gut contents. The structure, mode of reproduction, and within-gut distribution of the latter are described. This may be the first report of an organism of this type and the first evidence of a consistent endosymbiosis in the gut of a herbivorous marine fish.