Mollie sick

Question
My mollie is keeping its fins close into its body and swimming funny.  It swimmes forward and backwards all twisted like.  It stops and goes randomly also.  It hides behind the filter or heater often.  It is a female and is not pregnant for sure because i have no males.  She has been acting like this for about a week.  What is it and what should i do?

Answer
is she fat??

i know this is gonna sound crazy but mollies can actually store sperm..so from one single mating they can keep having fry until the sperm runs out & they can keep the sperm alive so it can be used as any given time..i know that sounds unreal but its true :)

if your 1000000000000% sure she is DEFFINATELY not pregnant then can you give me EVERY symptom??

oh i know her fins are clamped and she is swimming funny & hiding...

is her back curved, has she gone off her food..anything slightly different??