• Water Stability of Crustacean Feeds:
• Shrimps (Penaeus vannamei, Penaeus monodon) are slow, continuous bottom feeders that manipulate and nibble feed pellets slowly using their maxillipeds and mandibles.
• To prevent rapid physical disintegration and nutrient leaching into the water, commercially formulated shrimp feeds must exhibit a minimum water stability of 2 hours (retaining $\ge 85\%$ of their physical dry mass intact).
• Correct Option: Option 3 (2 hours).

• Feed Attractants in Aquaculture:
• Aquatic animals locate and ingest feed through chemoreception (olfaction and gustation).
• Feed attractants are low-molecular-weight substances incorporated into artificial feeds to enhance palatability and stimulate voluntary feed consumption, especially when replacing fishmeal with less palatable plant ingredients.
• Prominent chemoattractants include betaine (trimethylglycine), free amino acids (alanine, glycine, taurine, glutamic acid), nucleotides (inosine-5'-monophosphate, IMP), and krill meal.
• nalysis:
• (Attractants): Correct. Directly stimulates feed search and ingestion.
• (Antioxidants): Preserve feed freshness by inhibiting lipid oxidation.
• (Hormones): Regulate physiology/growth, not feeding stimulants.
• (Pigments): Impart coloration to flesh or exoskeleton.

Correct option: (3) Attractants