I have come back from two days away and have been unable to find my royal gramma for longer than five minutes. Recently my firecracker goby died. My cleaner shrimp subsequently ate it and died soon after. I could not see any signs of disease or parasite. Do royal grammas hide from time to time to grow etc? Or is it hiding to die? I currently have a scooter blenny and a spotted mandarin in the tank along with a selection of inverts. What other fish will be good to go in my 58l Boyu Orca?