my female auratus has a little float

[MrPower]

het everyone, im new to the site,
i bought a new female auratus today, it was fine at first, eats well.
but after a couple of yours in the tank she seems to have her tail end float up a bit on her.
if she relaxes her tail slowely risses and she has to push it down.
this is really wierd to me, any ideas?