Shaky Molly

[Swordtail]

I have a Molly which has gone all wobbly and shaky. She tends to stay in one spot (at the surface normally) and wobble from side to side.
Any ideas?

 

[DrOizo]

Thats called shimmying, How old is the tank, what are its water params, how big is the tank, How many fish are in it etc. If its a new tank the shimmying is probably due to high nitrites through an uncycled tank. Shimmying is caused by stress and bad water conditions is one reason why they do it