Happy Aquarium: Egg Hunt Prize Revealed -- Glowing Egg
Since Happy Aquarium still has no item storage, the eggs will have to be stuck in your tank until you've collected everything. You can also sell the eggs for coins. Common eggs are Swirly, Sunny, and Royal, which sell for 40 Coins each. Uncommon eggs, Zig-Zag, Polka Dot, and Wavy, sell for 40, 64, and 64 Coins, respectively. And Rare eggs Oval, Striped, and Star, sell for 64, 96, and 400 Coins, respectively.
After many weeks, the Rare Striped Egg that was giving me so much trouble finally appeared, and the Glowing Egg was dropped into my tank. It doesn't exactly glow, per se, but it does get all sparkly and it segues through a rainbow spectrum of color! And if for some crazy reason, you don't like it, you can sell it for 400 Coins.