Effect of a water conditioner on ornamental fish behaviour during commercial transport

Millions of ornamental fishes undergo transport every year during which they experience high levels of stress and prolonged recovery. Studies aiming to refine welfare during transport have generally focused on maintaining water quality to minimise stress, with far less consideration of whether the addition of water conditioners containing herbal extracts to transport water could provide additional stress reduction beyond that obtained by maintaining good water quality. No study has previously tested this on a commercial scale. The aim of this study was to test the effect of Stress Coat®, a commercially-available water conditioner which contains Aloe vera, on fish health and behaviour during commercial transport. First, we tested the effect of the water conditioner on the behaviour of guppies (Poecilia reticulata) post-transport in a simulated transport in the laboratory (bags with Stress Coat® n=6, control bags: n=6). In a second experiment, we added water conditioner to the shipment water of variatus platy (Xiphophorus variatus) for regional transport from a UK wholesaler to UK retail stores (< 8 h transport time) (bags with Stress Coat® n=11, control bags: n=11). Finally, the water conditioner was added to the shipment water of variatus platy for international transport from a farm in South-East Asia to a UK wholesaler (> 30 h transport) (bags with Stress Coat® n=16, control bags: n=16) followed by a second transport by road to local retailers (< 9 h) with no addition of Stress Coat®. Behaviour was monitored following the simulated transport. Water quality, behaviour, mortality and visible injuries of fish post-transport were monitored following both the regional and international transports. The effects of the water conditioner were variable between studies, but overall it reduced levels of erratic swimming and reduced biting behaviours following the simulated and international transport. The water conditioner did not significantly affect water quality, mortality or visible injuries post-transport and mortality was low throughout. Overall, adding Stress Coat® to the transport water of ornamental fishes appears to improve behavioural indicators of welfare, in particular reducing the occurrence of erratic swimming and biting behaviours.