01 · AquaGrow
What it is
Larval development should be assessed by trained observation, not tank age alone. Some variation is possible, but a widening difference with weakness needs investigation. This guide does not assign a universal day-by-day vannamei schedule.
Signs to watch for
- A sample contains unusually different developmental stages.
- Abnormal limbs or incomplete-looking moults are observed.
- Development slows alongside weak feeding or losses.
Common causes
- Starting lot quality or stage varies.
- Nutrition or environmental conditions are unsuitable.
- Health problems, chemical events or assessment errors need investigation.
How to confirm the cause
- Use a trained microscope assessment of representative samples and compare consistent stage records.
- Review source lot, water/temperature trends, feed and recent inputs; seek health testing when indicated.
What to do immediately
- 1
Verify the stage assessment and water/air readings.
- 2
Review feeding suitability with the larval technician rather than adding minerals automatically.
- 3
Keep the lot traceable and arrange assessment if the trend continues; do not mix batches to conceal variation.
Prevention: your practical checklist
- Assess starting lot quality and keep lots separate.
- Use stage-based feeding and stable system management.
- Record stage observations consistently across shifts.
When to call an expert
- Get urgent help if moulting or development problems accompany increasing deaths.
- Seek specialist review for persistent stage differences or repeated deformities.
Farmer questions
Does every stage difference mean disease?
No. Source quality, environment, feed and sampling can contribute. Investigate the trend with a trained technician rather than naming a disease from tank age.
Should I add minerals to force moulting?
Do not use minerals or other inputs as a universal correction. Establish the stage, water chemistry, nutrition and cause before choosing any input.
Can an old tiger-shrimp schedule be used for vannamei?
Not automatically. Species, stage and operating systems differ. Use an appropriate validated hatchery plan and current specialist advice.
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.
- Microbial communities associated with zoea-2 syndrome (2023) ↗ICAR-CIBA authors, Frontiers in Marine Science; association study, not proof of a single cause
- P. vannamei digestive development across larval stages (2020) ↗Rojo-Arreola and colleagues, PLOS ONE; original research, not a treatment trial
- SHAPHARI hatchery operating guidelines — production, biosecurity and records ↗MPEDA; linked guideline, not AquaGrow certification or a legal-compliance audit