Mucus-secreting lips offer protection to suction-feeding corallivorous fishes

Of the 6,000 reef fish species, only 128 feed on corals 1, 2. Despite being widely available on tropical reefs, corals appear to represent a particularly challenging trophic resource, with mucus- and nematocyst-laden tissues spread over a sharp coral skeleton. Here we report that coral-feeding tubelip wrasses use highly modified lips to suck material from the coral surface. These lips have a specialized mushroom-like lamellar epithelium that secretes mucus. This mucus may facilitate suction and reduce damage by nematocysts in a manner akin to anemonefishes. The remarkable lip specializations observed in tubelip wrasses highlight the potential role of soft tissues in shaping the trophic ability of fishes.