I don't know how it happened but the nitrates in my 50g jumped up pretty fast. This morning it read about 40 and my ghost shrimp were picking his tentacle apart. :\ I did two 30% water changes and brought it down to a little below 20. This is what he looks like now :[ Still breathing, slow and heavy, but I don't think he'll make it... I just noticed that one of his tentacles is cleanly cut off. I don't know if a crab did this or if the ghost shrimp ate it.