I used my daughters fathers credit card without permission from him to pay a phone bill, could this harm my parental rights?

An isolated incident of non authorized use of a credit card is hardly grounds for a person to declared as an unfit parent.

If this is the only issue I believe there is little to be concerned over.
I see it like having your child taken away if you get a parking ticket. Not reasonable or likely.

Well if he presses charges , and you are arrested for theft, they can use that against you, Are there other matters to show you unfit ?

An isolated incident of non authorized use of a credit card is hardly grounds for a person to declared as an unfit parent.

If this is the only issue I believe there is little to be concerned over.
I see it like having your child taken away if you get a parking ticket. Not reasonable or likely.

Hate to disagree here but as Fr_Chuck has said it is theft. A parking ticket is a much less offense. You wouldn't normally get arrested for it unless you didn't pay it. As for using a credit card without permission arrest can follow easily.

It depends on what the father does. He could prosecute you for theft which might (though unlikely) result in jail time. But this lone incident would probably not be enough by itself. How did you have his credit card in the first place?