Aquariums: Pom pom crab

I just did a water change so excuse the mess floating around but I just impulsively bought a pom pom crab. He immediately glued himself to the algae and no one has seemed to bother him and vice versa. Is there anything I can do to expand lifespan? I have read that they die very easily. My tank is a 10gal heavily planted with rocks and driftwood. I was also wondering about the lack of “poms” on him, but apparently that’s normal with molting. I’m most curious about his/her age