01 · AquaGrow
What it is
Larvae and seed need oxygen dissolved in their tank water. Low dissolved oxygen (DO) can become urgent. Appearance alone cannot measure oxygen or identify the cause of losses.
Signs to watch for
- Air flow becomes weak or uneven.
- Larvae or seed swim weakly or gather unusually.
- Feeding falls or new deaths appear.
Common causes
- Blower failure, blocked diffusers or an interrupted power supply.
- Oxygen demand rises with animal numbers, feed or waste.
- Poor mixing leaves parts of a tank less oxygenated.
How to confirm the cause
- Check a calibrated DO meter at representative tank points and the relevant depth.
- Check the air supply safely and record stage, temperature and time. Use the hatchery’s stage-specific operating plan, not pond ranges.
What to do immediately
- 1
Restore the planned, safe air supply or trained backup operation. Keep people away from faulty electrical equipment.
- 2
Measure DO and inspect larvae while calling the hatchery technician; do not wait for visible deaths.
- 3
Avoid extra feed or unplanned inputs during distress. Have the technician adjust the stage-specific feeding plan.
- 4
Monitor recovery across affected tanks. Do not move weak stock into clean batches to make space.
Prevention: your practical checklist
- Check diffusers and air distribution before stocking.
- Test backup air and power with trained staff.
- Match stocking and feeding to the system and keep water/air records.
When to call an expert
- Seek immediate help for weak swimming, deaths or an air failure that cannot be restored.
- Investigate repeated low readings even if larvae temporarily recover.
Farmer questions
Can I use the farm DO range for larvae?
Do not copy a grow-out pond range into larval care. The hatchery technician should set operating limits for the species, stage, temperature and system. Distress needs action whatever a single meter reading says.
Do bubbles prove the tank has enough oxygen?
No. Bubbles show air movement, not the oxygen available everywhere in the tank. Check DO, air distribution and animals together.
Will an oxygen product replace the blower?
Do not rely on an untested product as a substitute for the planned air supply. Restore safe aeration and obtain technical advice before adding inputs.
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