Gas Bubbles ?

[BioFish]

My mandarin is swimming at the top. I don't have experience with any fish doing this. Any help before I lose him??

 

[BioFish]

It was late last night and scared me but here's some more info.
I found her swimming close to the surface so I cut the powerheads off and got some food. Thats when I noticed her problem.Her back was touching the surface of the water. She looked alert and using her fins. I cupped her body in an attempt to fun my fingers down her body to find the air bubble. She shot out of my hand and dove into the rockwork. She never resurfaced. After lots of research for a couple hrs I found some good info. GBD is rare in marine fish. Without any abrasions it didn't seem likely. Next was Swim bladder disease, but that is also far more prevelant in freshwater. Then I stumble across a very short sentence. Upset stomach from eating a new food can cause your fish to be unable to control bouyancy. As I posted yesterday she had finally ate frozen food. I had used a mixture of foods that I feed my coral that included euphasia pacifica plankton. It's larger than mysis and didn't expect her to be able to eat it. I was very surprised when she sucked it down. This morning I found her huntin pods in the rockwork like nothing had happened . I would've been very hurt if she died the same day as accepting frozen food. Hopefully my experience can be of use to someone else since it took me a sleepless night to discover the problem.

 

[NPCivic]

My brother's female mandarin does this once or twice a week and always at night. She kinda floats there for awhile and the next morning she's perfectly normal. So I think that it is just something that they do. Oh and one more thing, she eats frozen mysis and trigger pods also. Hopefully, this puts some ease to your situation.