the last two days i have found five gold fish each day laying by the pond with their heads missing does any one have any idea if a heron would do this or would they eat all the fish. if not a heron any ideas what it may be.
Almost certainly not a heron. They eat the whole thing in one gulp.
With all the heads missing it sounds to me as if one of the mustelids (weasel/stoat) has found your pond and its easy pickings.
Depending on the surround of your pond, you may be able to sprinkle sand on the ground right around the pond. You will see the spoors in the morning and will have a better idea of the perpetrator.