I'm not sure exactly where to put this, so I'll try here.
I'm in NY and building an outdoor enclosure for a 3" RES. It's 125 gallons in the main pond, 18" at the deepest part, with maybe another ten gallons in an upper pond. The pond takes up about half of the enclosure, while the other is a turtle safe garden.
I'd really like a land based turtle that could live in the "garden." My RES is very people friendly and has never shown any interest in feeder guppies, so I don't think s/he would be aggressive towards another turtle, and if I got a land based turtle they really wouldn't even run into each other much. The turtles could both be introduced to the new enclosure at the same time.
Basically I'm worried that the new turtle might pick on the RES, and also that it could fall into the pond and drown if it's not an okay swimmer. There will be plenty of places for it to climb out, but still. Any ideas on species?