01 · AquaGrow
What it is
Fouling means material or organisms have collected on an animal’s surface. Ciliates are tiny single-celled organisms that may be involved, but debris and other organisms can look similar. Microscopy and water assessment are needed.
Signs to watch for
- Attached material is observed during trained examination.
- Swimming or feeding weakens.
- Fouling recurs with dirty surfaces or poor tank conditions.
Common causes
- Water or organic-waste conditions favour attached organisms.
- Contaminated water, live feed or equipment introduces material.
- A different health problem may be mistaken for fouling.
How to confirm the cause
- Ask trained staff or a laboratory to examine suitable fresh samples and identify what is attached.
- Review animal condition, water tests, waste and sanitation history; photographs alone are not enough.
What to do immediately
- 1
Check DO and water and call the hatchery health professional.
- 2
Keep affected tools and lots separate and arrange representative samples.
- 3
Review waste and feed management with the technician. Do not scrape delicate larvae or apply a chemical bath from an old manual.
Prevention: your practical checklist
- Maintain tank, line and equipment hygiene between batches.
- Check live-feed and intake-water quality.
- Include consistent microscopic observations in the health plan.
When to call an expert
- Escalate immediately if fouling is accompanied by distress or rising deaths.
- Seek investigation for repeated findings across batches or uncertainty about organism identity.
Farmer questions
Is every attached growth a ciliate?
No. Debris, bacteria, fungi and other material need different interpretations. Ask for appropriate identification rather than choosing treatment from appearance alone.
Can I use a pond fouling treatment on larvae?
Do not copy a grow-out treatment to larvae. The species, life stage and system must be considered by a qualified professional.
Does cleaning the water prove the batch is healthy?
No. Track the animals, feeding and survival after any management correction and follow the health professional’s sampling or testing plan.
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.
- SHAPHARI hatchery operating guidelines — production, biosecurity and records ↗MPEDA; linked guideline, not AquaGrow certification or a legal-compliance audit
- Hatchery operations and assessment framework (2007) ↗FAO FTP 446; historical P. monodon manual, not a vannamei treatment protocol