Pets from the 87 cartoon
 

The turtles seem to have quite a few pets they don't show that often. Like Michaelangelo's pet pigeon Pete. He was only in one episode, What's Michaelangelo Good For. He also had a pet goldfish named Maxwell who was also only in one episode, Donnatello's Degree. There was never an explanation of how he got those pets or what happened to them after season 4. At least in Polly Wanna Pizza, we know what happened to the pets.