Koi Under Attack!

[mickba]

I just went outside and found a koi about 5 metres from the pond, being eaten by ants but still alive (still is half hour later). I went to inspect the other fish and at first thought they'd all gone, but found them packed into a sump at one end - but not the full quota.

Come to think of it they didn't rush for food this morning.

For the past week we've been admiring a new bird in the area - looks mainly white in flight, but brown when landed/perched - and heron shaped!

I assume that's my problem - now what?

I guess I have to net it for now, but I do have an electric fence energiser. Do these birds walk up to the pond or land in it?