Howdy and welcome.
Very unlikely you or kiddos could be harmed in any way by water from a spring fed pond, or even a catchment pond for that matter.
What kink of fish do you have? Small sunfish can be startling and a little annoying, if you're just floating about holding still, but won't cause any harm. The effect depends somewhat on the age and disposition of the kids.
Also, some kids don't like walking through a lot of muck when going in and out of the pond...a load of sand or fine gravel can fix this, or a small dock.
