I never expected a turtle to be very interesting, so I was in for a surprise when I brought Donatello home.
When I brought him home, he was in bad shape. His previous owner hadn't taken proper care of him. He had a fungal infection and moss completely covered his shell and was growing longer than his legs. It was so bad that we had no clue he was a painted turtle because you could see no colors in his shell. We treated the water and gave him gentle sponge baths until the infection went away. I was worried for him at first, but he was extremely hardy.
He is the exact opposite of what I expected of a turtle. I'd always assumed they'd be a bit boring, but he definitely isn't! He likes to take "showers" by standing under the falling water of the filter. He swims laps around the tank. When I enter the room, he'll get excited, jump off his rock into the water and swim excitedly towards me. If I put my finger to the glass, he'll swim with his nose by my finger. He does the same when the cat puts her paw on the glass. He and the cat have a special relationship one rarely sees between a cat and a turtle. The cat will sit and watch him swim and he gets excited when he sees her and swims towards her.
He is easy to feed. We feed him several aquatic reptile pellets daily. We also buy feeder comets and let him catch fish as he needs. This not only helps him self regulate his feeding, but provides stimulation and a more balanced diet. Occasionally, I give him some pieces of veg and fruit. He really likes apples, but won't touch leafy greens for the life of him.
I keep a large tank filled with water and a large rock so he can climb out of the water to sun bathe. I keep his tank next to a window so he can enjoy the sunlight. I use a filter and change the filter every 2-4 weeks depending on how dirty it gets. I also keep a small water heater going to keep him from being too cold. Every week, I remove some of the water and add fresh water. Once a month or so, I take him out of the tank, dump the water, scrub the rock and sides of the tank with vinegar and water. I rinse it and refill with water with a dechlorinate. I give him a gentle sponge bath before putting him back in.
He doesn't like to be picked up, but is easy to handle. He does like to have sponge baths, as long as his feet are touching the ground/sink when I'm holding him.
I've heard a lot of people say that turtles only live 25 years in domesticity. However, his previous owner had him for 25-30 years before I took him home 5 years ago and he shows no signs of slowing down! He's a low-maintenance, interesting and fun pet. Once the initial purchases are out of the way, turtles are an affordable pet.