i have one (a painted turtle ive had for almost 1 year and 3months!) and hes in a 10 gallon tank with a 'pile' of rocks (a sturdy stack for a basking area), an undergravel filter, and a piece of a small flowerpot that he hides and sleeps in. its about half full of water and he is about the size of my palm. he seems comfortable yet i feel like hes lonely

what should i do???
Should i get him a friend?

Should i buy him a bigger tank?

Any suggestions?
