Practical fish-health skills
Scrape, culture, PCR: which test answers what?
Different tests answer different questions. Ask the examiner what is being tested and what a negative result can exclude.
External examination and wet mounts
These can help identify visible tissue changes and some external parasites. They do not screen a fish for every virus, bacterium or internal condition.
Culture and laboratory tests
Bacterial culture, susceptibility testing, histology and targeted viral tests may be appropriate. Sample choice and handling affect usefulness, so contact the vet or laboratory before collecting or posting material.
Bring a concise timeline
Include fish origins, symptoms, losses, water readings and treatments with dates. Ask about the expected result time and what to do while waiting. Do not move sick fish without professional instructions.
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.