I bought one of these about 4 weeks ago and he has been doing well in my QT that has been established for some 6 months now. Was always going around picking at the rubble rock, sand, etc. The past 3-4 days he has been hiding and not eating. he will nibble but thats it. He didnt this when I first brought him home but once I fed garlic with his food, he took right to it. Im feeding mysis with Vitamin C and garlic. I checked the ammonia to make sure I was not incurring a spike and its 0. Its a 30 gallon long. I have run 6 other fish through it so I know its good. Temp is 80. His color is good. I do 5-8 gallon water changes every other week. Any idea as to what could be going on? are they "moody" fish per say? I have never had trates in the tank either so its not this. Any ideas?