These mini aquariums measure 3 inches and include 2 fish that expand up to 5 times their original size when submerged in water, reaching full growth within 3 days. Each set contains 3 aquariums for multiple play options. The fish come in assorted neon colors, including blue, pink, and green, adding visual appeal to play spaces. Designed for children ages 6 and up, these expanding fish serve as an engaging way to introduce basic scientific concepts. They also function as versatile party favors, stocking stuffers, or small prizes. The product is backed by a replacement guarantee in case of dissatisfaction.