Standard 4-layer packaging for air-exporting live groupers:
Inner layer: Double-layered, heavy-duty live fish bags
Place the fish inside with water filling only one-third of the bag; inject pure oxygen (not ambient air). Inflate the bag so it is full but not overly taut (to allow for expansion at high altitudes); twist, fold, and tie the neck securely. Tie the two layers individually to prevent punctures from sharp spines causing leaks.
Middle layer: High-density Styrofoam box (wall thickness ≥ 3cm)
Place absorbent sponge or paper at the bottom of the box. In summer, include sealed ice packs (ensure they do not touch the fish directly to avoid frostbite). Close the lid and seal all seams with tape to ensure thermal insulation and prevent leakage.
Waterproof layer
Enclose the Styrofoam box in a large plastic bag and tie it securely; this prevents the outer carton from getting wet in the event of any seepage.
Outer layer: Heavy-duty corrugated cardboard box
Place the unit inside the carton, seal it, and attach the required labels.