Depressed Fish?

[Raindropsfly]

I have a black molly in a 10 gallon tank with 4 other fishes and 2 algae eaters. Everyone else seems happy swimming along, but the black molly stays in a general area with its fins lowerd most of the time. How do i make her happy again?

Here is a video.
YouTube - Sad fish help

 

[siva]

Okay that video was of a white fish, not a black one? Okay if your mollies fins are suddenly clamped and it's acting strange you need to test the water. Do you have a test kit?