Behaviour & health
Bottom-sitting and clamped fins
A change from a fish’s normal behaviour is a reason to investigate, not a diagnosis.
Observe the whole fish
Look at breathing, balance, skin, fins, appetite and whether other fish are affected. Note water temperature and the duration of the change. A fish resting in cold conditions is different from one suddenly deteriorating.
Check the water and equipment
Test the water and confirm flow and aeration. Review recent cleaning, transport, new fish or treatments that might explain a sudden change.
Reduce unnecessary disturbance
Avoid repeated netting to make the fish move. Keep the environment stable and get professional advice for persistent or worsening signs.
Escalate promptly
Breathing distress, inability to remain upright, significant wounds or several affected fish deserve urgent help. Provide the full history and readings rather than asking for a treatment based only on posture.
Record what changed
Note whether one fish or the whole group is affected, when you first noticed it and how the fish respond to normal activity. Keep water results and recent maintenance with the record.
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.