Personalized Mermaid Toddler Long Sleeve T-Shirt. Mermaid with blonde hair Toddler Long Sleeve Tee - Pink. Always be yourself...unless you can be a mermaid, then be a mermaid. A great design for any little girl who dreams of being a mermaid. A classic for Fall, Winter and Spring, these long sleeve toddler t-shirts are sure to be a staple in your child's wardrobe. Whether layered or alone, this t-shirt is soft yet durable enough to stand up to your toddler's playtime demands.