I had one in my 4g pico tank and it was rare to see him in there. They are really really tiny. My crab also lost it's pom poms and died. Not sure if he just couldnt eat anymore since his anemones were gone or if it was just his time.
I would suspect that you wouldnt see it at all pretty much in a 75g tank.
If you like crabs, they have emerald crabs which are bigger and quite amusing to watch. Mine do a little dance at the front of the glass. lol
Or maybe a porcelain crab, also a bit larger and he waves his little arms to capture suspended food, also fun to watch.