Hey.
My mystery is also in my DT. In my case, it hid for 2days on the 3rd day it decided to wonder out so to ease the problem i also placed an urchin a diamond back goby and a splendid dotty back.
Who took the beating? The goby. The goby unable to fend for it self got beaten so bad i havent checked but i placed it in my sump. I dont have much hope for it but if it pulls through ill get him a pair. Soon as he went into the tank he started working on my sandbed (thats why i got it)
The mystery got some rips on its fins but seems to be able to out swim the larger bullies. As for the splendid dottyback its also able to fend for itself.
The urchin....really pisses off my picasso trigger because he cant bite it.
So i guess now. Im looking for a diamond back goby and a midas blenny