Personalized 5th Birthday Mermaid Youth T-Shirt. Cute mermaid princess rides on her rainbow seahorse and surrounded by her fish friends. Happy birthday to the 5 year old on her 5th birthday. Let the good times roll in a durable T-Shirt that takes kids from school to play in an amazing array of colors. 5.0 oz., pre-shrunk 100% cotton. Seamless 1x1 rib collar.