Ah, I see. You started a thread that got locked, and assumed because of my name that I eat sushi. Maybe you should read other threads instead of trolling. There's currently one that not only explains where the nickname came from, but also states that I don't eat sushi. Don't troll me. Thanks.
I don't know, it's hard to tell by patterns as they can be different either by age of the crab or even just within the same species. If the shape of the body, the claws, and the pattern are the same, my guess would be they're the same kind. The most important way to ID is by the shape of the body & claws. At least for those of us who don't study them scientifically!
I'm really good at IDing hitchhikers, but my advice is usually not taken on tank maintenance LOL. Best bet for advice on that would be starting threads to get as many answers as possible on any general tank questions you may have. Welcome to the hobby!