Mandarin sluggish and not eating, Help!

[Vagabond]

As the title says, my Mandarin, as of two days ago, has become very sluggish and isn't eating.

Normally he is very active; constantly hunting for pods in the LR, always racing to be front and center when anybody approaches the tank, and eating mysis voraciously when I feed.

For the past couple of days he has been hanging around the back of the tank on the sand bed, not venturing very far, and has no interest in eating.

His color is still good, he does not appear to be having any respiratory problems, fins and gills all look fine.

I have not added any other tank mates and my clowns and firefish are doing great. All of my corals are very happy as well as all inverts.

Water parameters as of today and after a 15% water change yesterday are:
Ammonia 0
Nitrites 0
Nitrates <1
PH 8.1
S.G. 1.025
Temp 79-81

I am about ready to feed the little guy some prozac!

Any ideas out there or something I may be not testing for, or seeing please fire away with questions.


I do have 2 BTA's in the tank Is it possible he got into it with one of them?They have never bothered each other before.