Massages help stressed fish

IF YOU are stressed, a quick massage can help you chill out. Could the same hold true for some fish? A new study demonstrates how tactile stimulation can reduce signs of stress in the surgeonfish Ctenochaetus striatus.

The surgeonfish like to hang out in corals and visit cleaner fish, which remove their external parasites. During this process, the cleanerfish direct their “clients” by touching their fins.

So researchers from Portugal, Switzerland and Australia decided to simulate the fishy grooming parlour in the lab.

They set up fake, mechanical cleanerfish models that could move. They looked at levels of the stress hormone cortisol in surgeonfish that were “cleaned” by the moving models and compared them with hormones levels in surgeonfish exposed to fake cleanerfish that remained still.

“Surgeonfish had significantly lower levels of cortisol when stimulated by moving models compared with controls with access to stationary models,” write the authors online in Nature Communications this week.

Researcher Dr Marta Soares from the ISPA University Institute in Lisbon tells The Irish Timesshe was not necessarily surprised to find that the fish who were being cleaned got some benefit from the tactile stimulation.

“Cleaners win so much in providing massages to clients and by manipulating their decisions; then what about clients? We [have] now confirmed that these fish (so-called clients) are indeed benefiting (stress reduction) and enhancing their health,” she says.

More generally, the experiments help to shed more light on fish sensory systems, she adds.

“We know that fish experience pain and adverse stimuli, maybe they have pleasure too.”