Stones to use in wildlife pond
I am in the process of building a wildlife pond and, as one side will be adjacent to a small seating area, I would like it edged with stones.
My favoured stones, based on size and colour, are the Highland Grey Rockery Stone (http://www.gardenoasis.co.uk/highland-grey-rockery-stone-pieces-p-2104.html) - however the description on this website says these stones are "not fish friendly".
I believe (although I may be wrong) that this is because of the high natural ph levels in the stones.
Does anybody know if the "not fish friendly" warning also applies to wildlife in general, or is it particular to fish - ie could my potential frog, newt etc visitors be harmed if I use these stones?