Mermaid Jello Cups are a magical way to celebrate a birthday or surprise any mermaid lover. This fluffy jello mousse is topped with white whipped topping waves, colorful sprinkles, chocolate seashells and a chocolate mermaid tail. They are simple to make and look spectacular on a mermaid dessert table.

Need Mermaid Birthday Party Ideas?
I’m a little obsessed with mermaid crafts and treats and have shared many mermaid party ideas over the years. Mermaids are playful and timeless, and a themed dessert like these Mermaid Jello Cups brings that ocean magic to any celebration.

These cups are based on the classic Jell-O Magic Mousse — a simple, fluffy mousse commonly made by combining flavored gelatin with whipped topping. The result is airy, slightly foamy, and perfect for creating a bright aqua “ocean” when you use a blue gelatin like berry blue. You can adapt the mousse in many ways, but for this project the blue color and mermaid-themed toppings make a striking presentation.

Mermaid Jello Cups Ingredients
Very few ingredients are needed; decorations are what make them special. To make the cups as shown you’ll need:
- Blue gelatin (berry blue or similar)
- Whipped topping (COOL WHIP) or Greek yogurt alternative
- Assorted sprinkles (mermaid-themed mix)
- Candy melts for chocolate decorations
- Canola oil or shortening (optional, for smoother chocolate)
- Mermaid tail mold (silicone recommended for detailed tails)
- Chocolate seashell mold
How to Make Mermaid Jello Mousse
Start by dissolving the gelatin in boiling water. For a typical batch, whisk 1 box (6 oz) of blue gelatin into 3 cups of boiling water and stir for two minutes until completely dissolved.

Stir in 16 ounces of thawed whipped topping (or two 8 oz tubs) until fully combined. The mixture will become light and foamy with a pretty aqua color. If you prefer a less airy texture, substitute an equal amount of Greek yogurt for a smooth, creamy alternative.

Pour the mousse into 6 ounce glass or plastic dessert cups, filling each about two-thirds full. Place the cups on a small baking tray, cover loosely with plastic wrap, and refrigerate until firm — up to 8 hours for best results.

Greek Yogurt Alternative
If you don’t want to use whipped topping, try the Greek yogurt option: dissolve the gelatin in boiling water, cool slightly, then whisk in an equal amount of plain Greek yogurt. The texture will be denser and creamier rather than fluffy, but still delicious and colorful.
How to Make Chocolate Sea Shells
Melt candy melts in short intervals in a microwave-safe bowl, stirring every 15–30 seconds to avoid overheating. For a smoother finish, add a teaspoon of canola oil or shortening per cup of candy melts. Use a spoon or a food-safe brush to add color or paint a layer of white to the bottom of silicone molds before filling with colored candy melts.

Tap the mold gently to remove air bubbles and level the surface with a flat edge if needed. Chill in the refrigerator for about 15 minutes, then carefully remove the hardened chocolates from the mold.

Chocolate Mermaid Tails
Choose a detailed silicone mermaid tail mold for delicate, lightweight tails. Work carefully when removing them — the fins and tips are delicate and may break if handled while too cold. Make extra tails in case some break on removal. To fill the mold, melt candy melts, add a small amount of oil if desired, spoon into the mold, scrape the top level with a straight edge, tap out bubbles, then chill until firm about 15 minutes.

How to Assemble Mermaid Jello Cups
When the jello mousse is fully set, top each cup with additional whipped topping or a swirl of whipped cream to mimic white waves. Add chocolate mermaid tails, chocolate seashells, and a scattering of mermaid-themed sprinkles — a mix of blue nonpareils, silver confetti, pastel jimmies and small candy pearls works beautifully.

These jars store well in the refrigerator. The mousse and chocolate decorations can be prepared a day or two ahead; assemble on the day you plan to serve for the best texture and appearance. The finished cups are whimsical, colorful, and a real showstopper on any mermaid dessert table.


Mermaid Jello Cups
Ingredients
- 3 cups boiling water
- 1 box (6 oz.) berry blue gelatin
- 16 oz. COOL WHIP whipped topping, thawed (or equal amount Greek yogurt)
- Assorted sprinkles
- 1–2 cups assorted candy melts (white, lavender, pink)
- Canola oil or shortening, optional
Instructions
- Whisk the boiling water and gelatin in a large bowl for about two minutes, until completely dissolved.
- Add the 16 oz. whipped topping and whisk until fully combined and light.
- Pour evenly into 6-ounce glass dessert dishes or clear plastic cups. Place on a tray, cover loosely, and refrigerate until firm (up to 8 hours).
- For chocolate seashells and tails: melt candy melts in short microwave intervals, stirring frequently. Add a small amount of oil or shortening for a smoother finish if desired.
- Spoon melted candy into silicone molds, tap to remove air bubbles, level the tops, and chill until set (about 15 minutes). Remove carefully from molds.
- When jello is firm, top with whipped topping or whipped cream, add chocolate mermaid tails and seashells, and sprinkle decoratively with sprinkles. Store in the fridge until serving.

If you love these mermaid jello cups, you might enjoy other mermaid-themed treats like mermaid rice krispie treats or a blue mermaid hot chocolate that share a similar color palette and playful flair.
