Moving to a new environment is stressful for a fish

The information below is now included with every fish sold, along with what to do when you get your Koi home, what to do if you see signs of stress, basic guidelines for keeping Koi, and detailed advice on using salt.

We take every measure to ensure our fish leave the farm in good health. If we are in any doubt, we won’t sell the fish, and if you are in any doubt, you should not buy the fish.

Moving to a new environment is stressful for a fish. Stress reduces the effectiveness of any animal’s immune system, including fish, making it more susceptible to infection or to the effects of a poor environment. Poor water quality or parasite infestation can cause redness of the skin, sulking, flicking or flashing, and if not addressed can lead to death. It could take 1-2 weeks for the new fish to exhibit these signs.

As a rule of thumb, if a fish is introduced to a pond and the introduced fish later shows signs of stress, then it is reasonable to assume that the new fish is not happy with it’s new environment or has caught an infection from the existing stock who have become acclimated to the water conditions. If a fish is introduced to a pond and the existing fish later show signs of stress, then it is reasonable to assume that the introduced fish are carrying the infection.

All water regions and ponds have a different chemical makeup, and over time Koi can become acclimatised and tolerant to less than ideal water conditions.

What can I do to help my Koi settle into its new environment? 

When a fish experiences acute stress from injury, disease, handling or transport, their body releases hormones and neurotransmitters that make the fish breath faster, over-hydrate and lose salt. This can lead to an osmotic imbalance as a result of ion depletion – the most life-threatening impact of stress. To counteract this, we recommend adding salt to their tank or pond water to a level of 0.75% and maintaining it at that level for one week before reducing the level gradually with your regular weekly water changes.

A freshwater fish’s blood has a higher concentration of salt than the surrounding water – 0.9% to be exact. Freshwater fish need salt – without it they would die. 10-15% of their energy from food is spent extracting salt from the water they are swimming in and then not losing it.