So I was doing my weekly water change on my 50 gal (stock is 20 neon tetras and a flying fox) and half way through vacuuming the gravel my flying fox swam right into the siphon and got caught at the gravel filter part. I broke the siphon as quick as I can and from what I could tell he seemed unhurt in anyway. It's now been ten days and all he does is sit in the corner of the tank behind a rock and he won't eat. He is normally very active and playful and is the highlight of the tank. Is there any thing I can do to make him feel better or calm him at all? any suggestions for helping a fish with "mental" issues?