I posted this crab on Reddit and got multiple suggestions, there’s a little bit of an argument in the comments.
What is this crab. He is at least 3 years old, though he was this same size when we got him. He lived with a mantis shrimp and some fish; also some soft coral but never did any damage to them. When he’s not being messed with, he’s usually a purply/red color, always has the white spots. He’s rounder bodied, not flat if that makes sense.
Help me ID

What is this crab. He is at least 3 years old, though he was this same size when we got him. He lived with a mantis shrimp and some fish; also some soft coral but never did any damage to them. When he’s not being messed with, he’s usually a purply/red color, always has the white spots. He’s rounder bodied, not flat if that makes sense.
Help me ID

