Personalized Jellyfish Jellies Sea Creatures Youth Long Sleeve T-Shirt. A school of jellyfish in pastel colors on a cute Youth Long Sleeve T-Shirt - White sea creature themed gift, great for National Oceans Month. youth long sleeve t-shirt. Shoulder-to-shoulder taping. Youth: S(6/8), M(10/12), L(14/16), XL(18/20)