The Sea Turtle (known as The Marine Turtle) is the thirty-ninth episode of the first season of the animated series, The Great Book of Nature.
Plot[]
The Yellow Fish’s young have eaten poison and are seriously ill. Dr. Turtle prescribes the only possible antidote: the seeds of a red flower that grows in a distant, dangerous section of the river. The blue fish volunteers to go get the seeds, but along the way, it runs into the perfidious Grandma Fox who likes to eat young fish.
Thanks to the help of a friendly trout, the blue fish completes its mission successfully, after having putt down its own life on the line. The young fish are healed, and all the denizen of the deep then join forces to rescue the blue fish from the trap of Grandma Fox, who is to be forever banished from those waters entirely.