Congrats Spirit, I have three hermies right now as my tank is only a ten gallon and I like big crabs. I have two Purple Pincher crabs and one Ecuadorian. Your little guy is probably a Purple Pincher. I agree with what Fran said, they are pretty easy but they do need certain things to live.
Number one most important thing is humidity!! These guys are not desert dwellers, they are from tropical regions and need it to be wet. In order for this to happen they need a water absorbing substrate. I use playsand, some people buy something from the pet store called Eco-Earth, it's pure coco-fiber. Sand is cheaper, get it from home depot or the beach. The ground should be nice and moist, not soaked and puddly but wet enough that you could make a sand castle in the sand, it can hold it's form.
Another way to make sure it's humid is having a lid that traps in water (it still needs to let in air too). I use a mesh lid with plastic wrap on all but a strip of the mesh.
Spray the sand with water (de-chlorinated) every other day or so to make sure the top layers don't dry out.
As for heat use a heating lamp, you can get one of those reptile bulbs that provide UVB and UVA rays and leave it on during the day, shut it at night (when it's cold get a night heat lamp that glows red, they can't be bothered by that color). Under tank heaters don't work well at all in the deep substrate and even on the side of the tank the heat only goes so far from the heater.
The sand needs to be double the depth of your crab's height so he can bury himself and de-stress and molt. If he can't bury completely he might die of stress or be forced to surface molt which is also stressful (and makes it look like the crab is dead, so be careful!). Crabs will usually bury for a few weeks after purchase to chill out and maybe molt. Remember they were all taken from the wild, shipped to pet stores and then probably bought and shipped to the place you won him at, very stressful for the little guys. So leave him be for a few weeks, no handling, if the camera scares him hold off on pictures. I've had crabs die within a few days of purchase and you cannot blame yourself for those deaths, it is all stress that early on, I usually say any deaths in the first two months can be attributed to stress usually.
Food is fun. Commercial foods contain a lot of chemicals that can slowly poison the crabs. Most people don't expect them to live long anyways so it goes unnoticed. these are so new to the pet world that no one really knows how to care for them very well, it's all a guessing game really. So as with dogs and cats, coming closer to their normal diet is best. They are scavengers eating dead animals and fruits and veggies that are on the ground. So feed meat, fruits and veggies. unsalted nuts are good too, they need a fat source so that's a good one. Crush up egg shells for calcium or buy reptile pure calcium.
I usually feed one fruit (strawberry, grape, melon, blueberry etc.), one veggie (celery, carrot, broccoli, etc.), one meat (seafood is a favorite, like shrimp but anything that is unseasoned, preferably raw is good. I just take whatever I'm going to have for dinner before it's prepared and give it to them). Every other feeding I'll give either a chopped almond, walnut or oatmeal soaked in Extra Virgin Olive Oil for fat. Every meal gets egg shell sprinkled on top. You can give basil and Parsley too. I know it all sounds complicated but it's not too hard. I just look in the fridge and grab whatever I see that is safe for them, they eat so little it costs nothing.
Other than those things I'll mention that they need extra shells, some around the same size and some slightly larger. Get natural ones, not painted. They can ship off and eat the paint and it is toxic to them. Not all natural shells are boring and plain, you can look in craft stores for cheap shells. PPs tend to like round openings.
Get him a friend (or more) once you've set up the proper exhibit.
They need a place to hide and they like to climb so climbing stuff like vines or wood would be good.
Water should be de-chlorinated, just use what you'd use to remove chlorine and chloramines from fish tank water but make sure it does not contain slime coat stuff.
They need one fresh water bowl and one salt water bowl. Not table salt of course but stuff you can buy for marine fish tanks, the most common one is called Instant Ocean, a big box will last for years! Follow the direction and fill a gallon jug with the salt water so you don't have to mix every time you change the water. Both bowls should be deep enough for the crabs bodies to fully submerge but they need to be able to climb out as well.
Okay so that was a lot of info all at once, sorry about that. They get passed off as throw away pets who live for a few months and then die. They are an animal which does need a certain amount of care or it will die long before it should and will not live a happy life. They are not expensive past the initial expenses. I only change out all the sand once a year, change food and water every three days (slightly rotting fruit is not dangerous for them at all-scavengers remember) and just scrape the surface for poop every day or so.
Well cared for crabs are so much more fun to watch than poorly cared for ones. They climb and eat and interact at a nice pace. When I owned them five years ago on gravel in a kritter carrier they layed there, I never saw them eat and they died every few months. I stopped owning them until last year for that reason. Now mine are coming up on their first year with me, WOOT! I never had one live past 6 months before.
Good luck with your little guy, my three are Titan, Ophelia and Aphrodite. But I recently re-sexed Titan and I think he's a girl, oh well I'm not changing his name. I like Anubis personally.
Here is a really great forum, please check out the list of safe and unsafe foods in the food section before you make your hermies their food.
HCA: Hermit Crab Association® :: Index