GST rate change on prepared or preserved crustaceans and molluscs applies from the notified effective date. Imposition of GST at 5% w.e.f. 22-09-2025 on crustaceans, molluscs and other aquatic invertebrates when prepared or preserved, effected by Notification No. 9/2025-Integrated Tax (Rate) dated 17-09-2025, which inserts these goods into Schedule I for application of the integrated tax at the prescribed rate from the stated effective date.