Mandarin sluggish and not eating, Help!

[Vagabond]

Thanks everyone for all the suggestions, much appreciated.

I wouldn't be so confused by his behavior if I just got him, but I have had him for over 8 months and from day one he ate Mysis like a pig. It is his sudden lack of appetite that concerns me and his shy behavior where before he had been very outgoing.

I usually feed him with a 3/4" clear piece of aquarium tubing. Until a few days ago as soon as the tube went into the water he would rush over waiting for his meal to descend upon him. It was even to the point where he would swim up the tube and dine. Now, when I put the feeding tube in the water he just swims away from it.

The jar method sounds like a great idea, however, my 2 cleaner shrimp and my peppermint shrimp would quickly find there way to the trough and bully the Mandarin out of the way. As it stands now the only thing keeping them away from the tube when I feed are my 2 clowns, whom also feed from the tube and protect it from the intruding shrimp (Quite comical actually, as the clowns will charge them or when they get the chance grab the shrimp by the tail and shake them until they run for cover).