Celebrate with mermaid magic using these 7 Mermaid Theme Foil Balloons, perfect for birthday decorations. Add a touch of magic to your little one's birthday celebration with our Mermaid Foil Balloons! Featuring 7 colorful and whimsical balloons, these decorations are perfect for creating a beautiful mermaid-themed party. Made with high-quality materials, these balloons will add charm and excitement to any birthday decor. Floating Time (Helium)The foil balloons, filled with helium, will stay full for 2-5 days. They may float for longer but will start to appear more deflated as they lose helium. Latex Balloons: will stay floating for 3 – 6 hours depending on heat and humidity.