Since he's been with me he's been running around, exploring, climbing and checking out shells almost all day. He rests/sleeps periodically for about 2-3hrs and then wakes up to continue the same routine.
My problem is, he doesnt seem to be eating or drinking! He's not touched the hermit crab pellets the first night. The second night he picked up a slice of carrot and was about to eat it but he fell backwards off the dish and dropped it. He never touched it since.
As for water, he would hover over the salt water dish and fresh water dish but not go in. The most I've seen was him dipping a leg or claw in them. I did find some poop in the saltwater dish yesterday morning though..
Does this all sound like he's doing ok?
The previous owner I got him from have been keeping him in low level substrate (gravel) in a 1 gallon tank with no saltwater dish. From what I can gather, she's had him for 4 months and he hasnt molted.
My set up is a 16 gallon tank with 6" sand. I live in a tropical country so humidity and temp has been stable at 80% and 26-27C.
What can I do to get him to drink and eat?
He also hasnt dug around much, just mainly walking and climbing. Is this normal behaviour?
Honestly when they are new from bad conditions it can take awhile for them to adjust. I wouldn't worry too much, he will eat when hungry, and remember land hermit crabs are nocturnal. It is possible he's done stuff when you aren't awake. Sounds like you are doing a good job of providing the correct environment- Just keep offering varied foods. Though, you could give them some common "faves" like : Unfiltered honey is great for new crabs because of its natural antibiotic properties. Also egg shells with some albuim (whites) still left in it. Mine literally eat 2 whole farm fresh egg shells a week! Coconut, especially fresh. Is also great for them, as its s high energy food. Unseasoned popcorn is also a huge hit with my guys. A cheap way to do daily proteins is just using unseasoned meat from your meals. 
