Well I do know that a painted turtle is a wild species.
The two Florida river cooters we have were purchased in a pet store in Florida and brought home on a plane. I do not know if they were farm raised or not. I do know they would not survive here in Connectcut.
We have a heat lamp, (they love to bask), an air stone, and a filter meant for turtle tanks.
Painted turtles can with stand cooler temps although they still need a heat lamp, and of course something they can rest on or climb on, they should never be with out a resting place. If you keep them during the winter they might naturaly slow down.You will also notice they eat their food under water.
My boy frend and I kept a baby one for a short period of time with a violet goby and a couple gold fish. He started to chew on the fish so we released him back in to his natural habitat. We now are keeping cichlids.
As far as health and diet are concerned we feet them floating, (the sinking kind polluted the tank) pellets, (ReptoMin), and occassionaly shrimp treats
and lettuce, and sometimes small fish,, (golfish, toughies, small wild fish) We haven't had any health problems, but if they stop eating or develop soft shells or fungus around the mouth that might signal a health problem.
Turtles stil make an interesting pet, even if you observe a wild one for a short period of time and if you do release him do it before it gets too cold.
If you keep him too long he might have a difficult time surviving hs natural habitat.