A massive 550,000 liter (150,000 gallon) exhibit at the National Marine Aquarium in Plymouth (United Kingdom) was scheduled for phased restocking after its renovation, so scientists from Plymouth University and the University of Exeter took the opportunity to observe the physiological and mental effects of fish stocking levels on people.

The researchers found that simply watching the shimmering underwater light on artificial decorations induced relaxation in the study’s participants.  But as more and more fish of different species were gradually introduced into the aquarium, the scientists measured greater drops in both blood pressure and heart rates, confirming the positive physiological benefits of fish-watching.  The fish-gazers also reported better moods after spending time at the aquatic exhibits.  Furthermore, authors of the study suggest that the more colorful the fishes and the greater the biodiversity, the more pronounced the health benefits are.

Deborah Cracknell, PhD Student and Lead Researcher at the National Marine Aquarium, conducted the study and believes it provides an important first step in our understanding: “Fish tanks and displays are often associated with attempts at calming patients in doctors’ surgeries and dental waiting rooms. 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.”

Countless studies have shown that spending time with nature (even artificial “green” spaces like parks) has major stress-reducing properties.  Watching aquariums (large and small) is no different.

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

Dr Mathew White, an environmental psychologist at the University of Exeter, said: “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. 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.”

Keep in mind the study focused on the health effects for aquarium watching only.  Having to take care of aquariums (especially complex, expensive aquariums like reef tanks) may be a whole other matter!

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