Recommended ranges in the sources
ACIAR says little is known about grouper juvenile tolerances, so these are guides, not hard limits.
| Species | Temperature | Salinity | Oxygen | pH | Toxic gas |
|---|---|---|---|---|---|
| Grouper | 25–32 °C | 20–32‰ | 4–8 mg/l | 7.5–8.3 | NH3-N under 0.02 mg/L |
| Cobia (levels held in the Kien Luong trial) | 27–31 °C | 27–32‰ | over 4 mg/L | 7.6–8.2 | TAN under 0.5 mg/L |
| Long-finned pompano (pond) | 26–32 °C | 25–33‰ | 4–8 mg/l | 7.5–8.3 | Ammonia under 0.02 mg/L |
| Red drum | 24–27 °C | 25–35‰ | — | — | — |
| Rabbitfish (pond) | 25–32 °C | 20–32‰ | 4–6.8 mg/l | 6.5–8.5 | NO2-N 0–0.05 mg/L |
A dash means no recommended figure in the sources read. No recommended oxygen or ammonia limits for seabass fry were found, so it is left out; 10–20‰ favours growth according to SEAFDEC.
Daily work
Measure and record
Log temperature, salinity, oxygen, pH, deaths and feed. A log shows changes before fish fall ill.
Siphon and exchange
Tanks: drain to under half each morning, siphon and refill (ACIAR). Match current to fish size.
Remove dead fish fast
Dying fish carry the highest pathogen load, so take them out at once.
Salinity in ponds and hapas
After heavy rain
For rabbitfish, SEAFDEC says keep 1 m to limit swings in water quality; a 1998 rabbitfish text warns that rain can kill fish in shallow ponds.
Low salinity is no sure protection
White spot has broken out at 5–10‰ in Taiwan. Amyloodinium also completes its life cycle in brackish water.
Mixing water
Use the mixing calculator on the Tools page to reach the salinity you need.