guppy femals back is curved

Question
my 2 guppies have a bow in there back all else is good they swim side to side and look like they broke there backs help

Answer
If they have been like that since you purchased them, then they have have Fish TB.  My recommendation would be to euthanize them humanly.  If they have recently developed this condition, then I am at a loss.  Feel free to send a follow up if you can think of any more information.