Hi ... I have a 13 week old chi with an open fontanelle approx the size of an English 5 pence piece. Will this close as she grows? Other than this she's a normal, happy, mischievous puppy

Some close and some do not. All 3 of mine had them. One closed fairly quickly and while they are smaller now than when they were puppies, the other 2 still have theirs. One is 2 years old and the other will be in 2 months so this is likely how they will remain.

__________________

And have your dogs led normal healthy lives despite the soft spot?
I'm totally paranoid after losing a pup I purchased last year ... She died at just 9 weeks from fluid on the brain

They certainly have.

Open molera is not the same as hydrocephalus.

Here is an article that you may find helpful:
Molera Statement

__________________

Tracey, take a quick look at this link...

Molera Statement

It is common for adult Chihuahuas to have an open fontanel/molera.
Chanel's closed, but Bella's remained, both are not affected by it one bit.
You just have to be a little more careful that your pup does not bang his
head, don't let him jump on/off furniture, etc, but personally I do that
either way.

__________________

Karen, we posted at the same time, same link. Great minds think alike,lol.

__________________

Many, if not most, Chis have a molera as puppies and some keep them through adulthood. As long as it is not too large where it is dangerous, Chis live completely normal lives with it. Toby still has a small one and he is a year old. It may close, it may not. It's not dangerous and in no way impacts his life.

__________________

Thank you very much to everyone who replied. Also thanks ladies for the link which I found very useful and informative