Shared with you
The "Teenage Mutant Ninja Turtles will return after these messages" and "We now return to Teenage Mutant Ninja Turtles" bumpers used going into and coming out of commercial breaks were not voiced by Pat Fraley as some believe. The voice was likely provided by a Murakami-Wolf-Swenson employee as opposed to a professional voice actor.
In the original comics, all four turtles had red bandanas. For the TV show, TMNT creator Peter Laird decided to give each Turtle a different color to make it easier to tell them apart: Leonardo has a blue bandana, Raphael a red bandana, Donatello a purple bandana and Michelangelo an orange bandana. This color scheme became so popular it eventually became a staple of the TMNT saga.
Townsend Coleman said the catch phrase "Cowabunga" was not scripted. He just blurted it out in an ad-lib and the studio liked it so much is became Michealangelos catch phrase.
At the time of its final episode, it was the longest running cartoon in American TV history. However this record was beaten two years later by The Simpsons (1989).
In this series, Splinter and Hamato Yoshi are the same person. In the original comic story, as well as both Teenage Mutant Ninja Turtles (1990) and Teenage Mutant Ninja Turtles (2003) , Splinter was Hamato Yoshi's pet rat. Nickelodeon would later reuse this plot device for both most of their media adaptions (minus Teenage Mutant Ninja Turtles (2014) and Teenage Mutant Ninja Turtles: Mutant Mayhem (2023) due to Hamato Yoshi being phased out of both versions) and the IDW comic book series (due to Nickelodeon licensing the rights to them).
Begining in Season 4, the show started phasing away Michaelangelo's nunchucks and began having him use the Turtle Line, a turtle shell shaped grappling hook used by all the turtles, as his main weapon. Starting in Season 5, the nunchucks were not even kept on Michelangelo's belt and disappeared without any explanation. This is a direct result of nunchucks being outlawed in many countries and these countries had to edit out any footage of Michelangelo using his nunchucks. Since the show went international, Murkami-Wolf-Swenson changed it for everyone.