New fish
The first week with new fish
Keep the first days calm and observe both the new arrivals and the fish already there.
Watch, then adjust
Check swimming, breathing, appetite and access to food. Some settling behaviour is expected, but persistent distress, injury or rapid breathing needs attention.
Keep testing
New fish increase the load on the system. Record ammonia and nitrite, along with temperature and any maintenance. Do not assume an established filter has unlimited spare capacity.
Avoid too many changes
Keep handling, unnecessary netting and sudden diet changes to a minimum. Follow the supplier’s advice on the initial feeding routine. Do not add another group of fish before understanding how the system responds.
Make help easy
If contacting WakeyKoi, include your order, arrival date, species, volume, test results and a clear description of the concern. Never put payment-card details into the advisor.
Keep a first-week diary
Record arrival time, behaviour, appetite, water readings and any concern you report to the seller. A brief dated record helps you describe what changed without relying on memory.
Sources & further reading
Original WakeyKoi wording, informed by the references below. Linked clinical resources explain the evidence and their scope; they have not reviewed or endorsed this website.
Related guides
Educational guidance cannot diagnose an individual fish. Breathing distress, severe injury or unexplained losses need prompt professional assessment.