It’s been said that dog is man’s best friend, but perhaps it ought to be fish. In the first study of its kind, researchers from the National Marine Aquarium, Plymouth University, and the University of Exeter analyzed the physical and mental responses of people viewing fish tanks, and the results showed several benefits.

The team noted that viewing aquarium displays led to a clear reduction in both blood pressure and heart rate, and that tanks with higher numbers of fish were more successful at holding people’s attention and increasing their mood.

Presented with a unique opportunity, researchers took advantage of the National Marine Aquarium refurbishing one of its main exhibits and beginning a phased introduction of new fish. This allowed them to assess heart rate, blood pressure, and mood of the study participants and the introduction of new fish simultaneously, highlighting the effect of number of fish.

Studies have shown that spending time in “natural” environments is generally soothing to humans, but very little research has been done on the effect of an underwater environment specifically. Deborah Cracknell, PhD student and lead researcher at the National Marine Aquarium, says there is a good reason there are fish tanks at the doctor’s office.

"Fish tanks and displays are often associated with attempts at calming patients in doctors' surgeries and dental waiting rooms," she said in a press release. "This study has, for the first time, provided robust evidence that 'doses' of exposure to underwater settings could actually have a positive impact on people's wellbeing."

The findings may be able to benefit those who don’t have the time, money, or means to reach the real "natural" environments that have calming benefits.

"Our findings have shown improvements for health and wellbeing in highly managed settings, providing an exciting possibility for people who aren't able to access outdoor natural environments," said Dr. Matthew White, an environmental psychologist at the University of Exeter. "If we can identify the mechanisms that underpin the benefits we're seeing, we can effectively bring some of the 'outside inside' and improve the wellbeing of people without ready access to nature."

In terms of implementation, aquariums could be looking at a whole new angle for marketing their environment.

"While large public aquariums typically focus on their educational mission, our study suggests they could offer a number of previously undiscovered benefits," said Dr. Sabine Pahl, associate professor in psychology at Plymouth University. "In times of higher work stress and crowded urban living, perhaps aquariums can step in and provide an oasis of calm and relaxation."

Source: Cracknell D, et al. Aquariums Deliver Health and Wellbeing Benefits. Environment & Behavior. 2015.