Does anyone know what these white spots are on this crab? This is the second crab that has them. The other one was covered and is now missing (presumed dead as I see another crab now living in his shell). I only had one fish (watchman gobie) in the tank and he died suddenly a few days ago. My levels had been fine until this all started and now I have low levels of ammonia (<0.15) and nitrites (0.1). I’ve been doing water changes to try to get it down but it’s not really moving. I guess my questions are 1. Is this a parasite killing my crabs? And 2. Why are my levels suddenly up when they’ve been stable?