Also known as Derring's Singing, Spelling Herrings
and just Derring's Herrings
. This a cappella group of amazing fish are from the 1959 Dr. Seuss children's book Happy Birthday to You!
They have been trained by Dr. Derring to sing and spell "Happy Birthday to You" as part of the traditional birthday celebrations in the land of Katroo, where they celebrate birthdays hard.