These guys are probably the best beginner turtle out there and something the size of a 40 gallon breeder aquarium or tub is about as small as I would go. They are quite active turtles and really enjoy space to explore. I currently have one living in a 40 gallon rubbermaid tub with a few fish and so far so good. Like Simon said they are mainly carnivores but will nibble on water plants from time to time. I feed mine turtle pellets, cichlid pellets, shrimp pellets, freeze dried shrimp, worms, frozen shrimp, fish filets, snails and crickets. Keep water temperatures in the mid to high 70's and have a strong filtration system as these guys just like any water turtle are pretty messy. They rarely bask when older but you should still provied a basking spot for them. I also have lots of floating Anacharis in the tank for my turtle to rest on.