University of the West of Scotland researchers have found the cannabinoid cannabidiol (CBD) could reduce stress experienced by ornamental fish being transported.
Their experiment involved variatus platys (variable platyfish), which is a popular breed of aquarium fish. 200 of the fish were acquired from a local wholesaler, quarantined for 2 weeks upon arrival at the University of the West of Scotland and prophylactically treated with Protozin. Protozin is used to treat common freshwater parasites such as white spot, velvet, and fungal infections.
When being subsequently transported, cannabidiol was added at nominal concentrations of 3.9, 7.8 or 15.6 mg/l, along with control and solvent control groups.
The researchers found those that had been transported in water infused with CBD displayed a decrease in stress-related behaviours, such as biting, chasing and swimming erratically. They suggest CBD produces a calming effect by potentially modulating neural pathways related to fear. No negative impact to the protective layer of mucus which covers fish skin was observed.
The lowest concentration found to affect a range of behaviours was 7.8 mg/l.
The ornamental fish industry is huge – a multi-billion dollar affair that sees more than a billion fish transported annually.
It’s an important finding as stress caused during transport can weaken the immune response in fish and anxiety-induced behaviours can result in physical harm; both of which impact animal welfare and the profits of vendors.
“Improving the welfare of fish transported internationally is of importance both ethically and economically,” said study lead, Professor Katherine Sloman. “Within the ornamental fish trade, we know that transport-induced stress can lead to erratic or aggressive behaviour, which can exacerbate levels of anxiety and potentially lead to physical damage.
Adding CBD to commercial water conditioners could transform the industry and help safeguard the wellbeing of countless fish, said Professor Sloman.
The full study report on the effects of cannabidiol in transport water on the behaviour of ornamental fish has been published in the journal Applied Animal Behaviour Science. The researchers point out the transportation stress used in this study was simulated only by movement on a trolley; so quite mild, whereas higher vibration levels are likely during transport in a vehicle.
In terms of funding, the research was supported by the University of the West of Scotland, Waltham Petcare Science Institute and Aquasense UK Ltd.
