Hi,
pond netting will solve the problem, but it's really ugly.
try running (tightly) some fishing lines across your pond. so that when those birds try to land, they will come in contact with the fishing lines and took off. If this don't work, you will need a deeper pond.
good luck!

I feel your pain having lost my large Koi last Wednesday 4/18. Friday I put plastic black netting over the pond and that seemed to do the trick. It also keeps my dog out of the water which keeps the house a lot cleaner. Good luck and buy yourself more fish....you will feel much better. I lost one and bought four:)

You could also get a jack russell.Mine chased the heron off.SHe almost caught him.I doubt he'll be back

lol thanks, the terrier sounds good to me, but my beau did string the wire off the ground, over the pond, parallel in lengths about 8 in apart, and seems like that did it. Just got some more feeders for the top pond, which was emptied, so they can start getting after the pollywogs. :>) Debbie

BTW we have koi babies now!! D

If you do it right, netting isn't that bad. I fought it for a long time until we lost half our fish. Scarecrow motion activated sprinkler didn't work either. The bird netting isn't ugly. You can't even see it until you're right on top of it. That's the only thing that worked for us. We like to get into the pond to clean and do maintenance, etc. (ours is approx. 3,000 gallons), so stringing wires around wasn't an option. Dogs only work if they're out there when the bird is around - which ours never was. (Why'd you put your cat in a shelter??)