Design custom mermaids of course! Add a few gems, pearls, pipe cleaners (?) and paint strokes and you'll have a few fine maids of the sea.
B let me design and cut out her first one (the largest version at top), then she took a stab at her own, more diminutive mermaid.
When the creating is complete, your little mermaids or mermen may enjoy a reading of Mermaids on Parade by Melanie Hope Greenberg. It's a story about a young girl in Brooklyn who joins the annual Coney Island parade to mark the beginning of summer. I'm still holding on to the last rays of summer sun before fall takes a stronghold.