I had a similar thing happen. My buddy, Brian, was fighting a steelhead. While he was bringing in the fish, it was followed in by three other steelhead. He pointed this out and I cast just beyond his fighting fish. I was using a thill float and bait. Next thing you know one of the following fish rose up and grabed my thill and yanked on it, it too was a buck. It didn't swallow it but just gave it a good bite. one of the stranger things I have seen.