01 · AquaGrow
What it is
NHP is infection with Hepatobacter penaei, an intracellular bacterium affecting the hepatopancreas. A pale digestive gland or soft shell alone cannot distinguish it from other health problems.
Signs to watch for
- Weakness, reduced feeding and poor growth or a thin appearance.
- A smaller, pale or abnormal digestive gland in affected shrimp.
- Soft shells, fouling or darkened gills may occur but are nonspecific.
Common causes
- The bacterium damages cells of the digestive gland. This is a specific bacterial disease, not another name for every case of hepatopancreas damage or AHPND.
- Similar signs can have other causes: AHPND, EHP and other digestive-gland disorders. Poor nutrition, oxygen problems and unsuitable water chemistry.
How to confirm the cause
- Ask for specific H. penaei PCR (a laboratory test for genetic material) testing with histological assessment where indicated.
- Give the professional your water, feed and mortality history; a general Vibrio culture is not an NHP test.
What to do immediately
- 1
Contact a qualified professional; assess oxygen, feeding and the wider pond condition.
- 2
Arrange laboratory examination rather than selecting an antibiotic by organ colour.
- 3
Follow the appropriate official pathway for any suspected unusual infection.
- 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 from a documented health programme and retain source records.
- Control animal introductions and protect ponds from contaminated material.
- Monitor water trends and avoid preventable stress, while maintaining a species-appropriate environment.
- 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 NHP the same as AHPND?
No. They involve different agents and diagnostic approaches, although outward signs can overlap.
Can a routine pond-bacteria plate confirm NHP?
No. H. penaei is an intracellular agent. Ask a qualified laboratory for the appropriate specific tests and interpretation.
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 Hepatobacter penaei (necrotising hepatopancreatitis) ↗World Organisation for Animal Health — Aquatic Manual (2019; historical chapter)
- Necrotising hepatopancreatitis — field signs; historical guide ↗NACA / Australian Government — historical Asia–Pacific identification field guide; not current surveillance