External parasites
Gill flukes: Dactylogyrus
Dactylogyrus are egg-laying monogeneans commonly associated with fish gills.
Why timing matters
Eggs can complicate control because a treatment that affects exposed parasites may not eliminate protected eggs. A follow-up schedule must match the exact product and conditions.
Leave gill sampling to trained hands
Gills are delicate. Have a competent professional decide whether a gill sample is needed; a skin scrape does not automatically clear the gills.
Breathing changes need prompt help
Share water results, oxygen information, recent additions and a complete treatment history. Ask what successful recovery and a useful recheck should look like.
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.