01 · AquaGrow
What it is
Yellow head disease is associated with yellow head virus genotype 1. Not all related yellow-head-complex viruses have the same disease effects, and yellow head colour alone is not a diagnosis.
Signs to watch for
- A sudden change in appetite, followed by reduced feeding and weakness.
- Pale body or yellowish head region in some affected animals; gills may change colour.
- Shrimp gathering near edges or the surface and a rapidly increasing mortality pattern.
Common causes
- YHV1 is an RNA virus. Much of the classic field description comes from black tiger shrimp; do not assume every sign or outcome is identical in vannamei.
- Similar signs can have other causes: Digestive-gland colour changes caused by feed, other infections or environmental problems. Low oxygen, WSSV or bacterial disease with similar distress and deaths.
How to confirm the cause
- Arrange genotype-appropriate YHV1 RT-PCR (a laboratory test for RNA genetic material) and other confirmatory testing through a qualified laboratory.
- Report pond history and species. A related-virus finding or yellow head colour must not automatically be reported as YHV1 disease.
What to do immediately
- 1
Check oxygen and stabilise aeration while contacting a professional.
- 2
Record the sequence of appetite change, colour changes and mortality; arrange suitable samples.
- 3
Use the competent-authority pathway if an unusual listed infection is suspected, rather than circulating an unconfirmed diagnosis.
- 4
Keep affected stock, equipment and water separate. Agree on safe disposal and any harvest or discharge with your professional.
Prevention: your practical checklist
- Use traceable seed with a relevant, documented health-screening programme.
- Control incoming water and carrier access; avoid unapproved movement of shrimp between farms.
- Maintain stable oxygen, feeding and water conditions and a written emergency plan.
- Assign nets, trays and boots to each pond; clean and disinfect equipment under the farm’s biosecurity plan.
- Keep seed-batch, feeding, water-quality and mortality records so a change is noticed early.
When to call an expert
- Call an aquatic animal health professional urgently if deaths rise, shrimp gather at the surface, or breathing becomes difficult. Check dissolved oxygen while arranging help.
- Arrange an assessment if these signs persist, feeding falls or growth stays behind the crop trend. Send water readings, recent input records and photographs; ask the laboratory how to collect samples.
Farmer questions
Is yellow head disease just a colour problem?
No. It is a specific infection requiring confirmation. Colour is a nonspecific observation and can be influenced by several other conditions.
Are all yellow-head-complex viruses YHV1?
No. The laboratory must distinguish the relevant pathogen. Closely related viruses are not interchangeable names for the same disease risk.
What should I record before asking for help?
Note the pond ID, culture day, recent deaths, feed intake, water test readings and recent changes. Ask the laboratory about suitable samples before adding a treatment. A photograph alone cannot confirm the cause.
Sources & further reading
AI-assisted educational content and translations, source-checked 17 October 2026. Not an individual diagnosis or prescription. Independent aquaculture-health and native-language specialist approvals have not been supplied. Sources do not endorse AquaGrow.
- Infection with yellow head virus genotype 1 ↗World Organisation for Animal Health — Aquatic Manual; linked chapter, not live surveillance
- Yellowhead disease — field guide; historical host descriptions ↗NACA / Australian Government — historical Asia–Pacific identification field guide; not current surveillance