Thanks for the info. This was near sunset when I noticed them doing the herding. I think it was deliberate, and planned. Didn't get to see them take any FHM, because the dog jumped in. Hopefully I'll see it again, and get a picture.
I have YP in the pond also, but I hardly ever see them. (1200 YP, vs 150 RES)
Jeff

12 yr old pond, 1 ac, 15' deep.
RES, YP, GS, FHM (no longer), HBG (decreasing), SMB, and HSB (only two have been seen in 5 yrs)
I think that's about all I should put in my little pond.
Otter attack in 2023.