Mermaid Party Supplies; Mermaid Friends party decorations. Happy Birthday Ribbon Banner. Invite the little mermaid to liven up your party. The banner features the happy mermaid with purple hair and spells out Happy Birthday. Each letter is within its own circle pennant, joined together with white ribbon. Perfect for any birthday celebration or sea themed party. Co-ordinating colours - pale blue, green and purple. 1 banner supplied; size 2.4m (8ft).