Herons sometimes spear fish, leaving holes and marks on them, but other times will snatch with those ugly beaks of theirs. The only way it would have dropped the fish would be if something startled it away or the fish was too big to consume. I'm thinking the fish are probably jumping.

Fish will jump for a variety of reasons. They will jump if parasites are bothering them (i.e. flukes, etc), but they will also jump if there has been a sharp change in ph, which irritates their skin. Test the water and see what your readings are. If the ph is low, add some baking soda to bring it up. I also use koi clay, which contains beneficial minerals.

I had jumpers this spring, which stopped when I adjusted the ph and used the clay.

I'll check the balances when I get home this evening. This is only about a 200 gal preform pond, so if this is the problem, how do i judge the amount to add? I understand that adding this will depend on the ph level in the pond. I have baking soda at home, but have never used koi clay.

i'm also going to be safe and add some netting.....

Good idea on the net. On a pond that small, I'd just add baking soda at a teaspoon at a time, let it sit for a few hours and then test it again. From the size of the pond, I'm assuming you have goldfish? I don't know if koi clay is beneficial to goldies or not.

I would also net a few of the goldies to see if you see any sign of parasites, i.e. red dots on the body or anything hanging from the gills or body.

I've even used baking soda in the aquarium to raise the ph. It's perfectly safe, when added in small doses.

Someone please jump in and tell me, if I'm wrong, but I didn't think gf jumped for the sheer hell of it like koi do. I would check for irritants, like the previous poster advised. I also think they will jump from a fungal or other infection as well. You might try salting the pond, if you ph checks out. Do you know your normal level? GF really don't mind a high ph. Mine runs 8.5+ on a regular basis. Also, I would watch to see if any of them seem to be flashing. (twisting in the water as they swim, or rubbing against pots or other objects in the water) If you do salt the pond, you should remove any plants that you can.

Yes they were goldies. I haven't noticed any odd behavior in any of the fish, but with the small pond, I shouldn't have any trouble scooping them up to look them over. Since I've had no problems for a very long time (as in years), I'm afraid I haven't been checking the levels. I haven't introduced any new fish ever (all my own babies from pond #1) and no new plants since summer last year. But I'll give it a thorough going over. And give the guard dogs a talking to! lol!

My goldfish will jump out of the water after a bug or gnat. My pond is set up so that they can't possibly jump completely out of the pond but they do jump out of the water at times. Glenda

Parasites can come in from many sources. Some I never thought of messed up my pond and I lost fish. Some parasites are dropped from the legs of birds that visit. Some live in the gut of animals and are shed in their droppings. Storms can suck up contaminated water and drop it elsewhere. Some lay dormant for long periods in the body of a fish and only hatch when the fish is under stress. Some, like cryptosporidium, even survive water department sanitation and come thru the tap. Sandy

Here is a link that might be useful: Some of the safe and not so safe critters in the water