Just like in humans, massage therapy lowers stress in surgeonfish, Ctenochaetus striatus, reports a study in Nature Communications this week. The work shows that in the coral reef ecosystem, when cleanerfish remove parasites from surgeonfish, the physical contact provides the added health benefit of lowering stress.

To mimic this tactile stimulation in the laboratory, Marta Soares and colleagues built look-alike models of cleanerfish and measured the effect on the cortisol levels in surgeonfish. The reduced cortisol levels indicate that just the physical contact, with no social interaction, is enough to lower stress, therefore implying potential health benefits of massage which so far have only been demonstrated in humans.