well since you say you bough the turtles I'm assuming you got it from a pet store, in which case, you're probly going to have a bit of a hard time getting it started(eating, drinking, doing turtle things..)3-toeds are one of the least active boxies.. if not THE least active of them all, which makes them even harder to get started.
anyway, newly accuired animals of most any species is going to need between 1 day to 2 weeks, some might take a little longer to become accustom to their new surroundings. if you want the turtle to be active get rid of the aquarium, infact through it in the garbage.. or buy some guppies, put the turtle in a 50 gal or bigger rubbermaid tub, no smaller than 50 gals, fill it with about 5" of top soil/sphagnum peat moss make sure the substrate is free of chemicles, I'm hoping you already have the proper UV lighting, lights should be on for atleast 12 hours to mimic summer-like conditions, basking temp should be around 95-100 cool side temp 65-70 degrees F, and high humidity, what are you offering for food? do you know if it's male or female? male turtles seem to like yellow foods better, where as females seem to prefer red foods(thats personal experience).
also, no turtle should ever be bought from a pet store, they're often parasite ridden and sickly, and buying one from a pet store will just fuel collecters, and there are plenty of captive bred born box turtles available in the pet trade now.
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