what is this parasite

I have discovered a parasite on some of my fish. It is visisible on the side
of a couple of my fish.

It looks like a small white tube about 1-2mm long and 1/2 - 1 mm in
diamater, sticking out of the body of the fish. like the tip of a worm
poking through the flesh. it is perfectly straight and seems almost rigid.
It is perfectly white.

infact it looks almost exactly like this: - exactly to scale, but white
instead of black. ( I'm talking about this thing: "-") and it's sticking
out of the body of the fish.

In Australia we have things called hundreds and thousands, that you decorate
cakes with. if you have seen them, it looks like one of them!

the fish try to scratch in the site where this thing is.

each fish affected has only one parasite, and each fish that has one
scratches.

please help me diagnose this problem, I have searched some diagnostic sites
with no luck.