Ideal salinity to attain good growth of milkfish is:

Correct option is A

Correct Answer: (a) 10–25 ppt
Explanation:
→ Milkfish are euryhaline but show best growth and feed conversion in low-to-moderate brackish salinities (~10–25 ppt) where osmoregulatory costs are moderate.
→ Very low freshwater or very high marine salinities can reduce growth efficiency.
Information Booster:
→ Hatchery larvae require higher salinity phases; grow-out ponds commonly use the 10–25 ppt window.
Additional Information (Other Options):
(b) Wider but includes extremes; (c),(d) too high and too low respectively for optimal growth.