Mermaid Birthday Decorations Market Report: Sales Volume, Market Share, Leading Brands & Market Trends

GREATRIL is the best-performing mermaid birthday decorations brand in July 2026, moving 11,000 units across 2 ASINs for 20.8% of Top 10 volume. MEICOLY follows with 10,000 units (18.9%), ahead of Creativity for Kids on 10,000 units (18.9%).

Volume is spread across 9 brands, with the top three holding 58.5% between them. No single label controls the shelf, which usually leaves room for a well-differentiated listing to take share without outspending an incumbent. Average selling prices among the leaders run from $6.98 to $11.33, which frames the price band a competing listing has to justify.

Based on July 2026 data, this shortlist surfaces the two kinds of ASIN worth keeping an eye on — the ones that just broke into the Top 10, and the ones growing fastest month over month. Specifically, one ASIN forced its way in: B0CKBD8W1Q booked 2K units at $7.99, with ▲ 100.0% MoM change. On the growth side, B0GXXYNLQD leads positive momentum with ▲ 300.0% MoM growth on 400 units, with B0GTNX9D96 close behind at ▲ 233.3% MoM on 1K units.

The two signals carry different weight. A fresh entrant means share has already changed hands — an incumbent gave up its place to make room, so any competitive set drawn up a month ago is now out of date. A steep growth rate works as the earlier warning: it marks demand that is still compounding, usually a month or two before the ranking catches up to it.