outdoor stock tanks...successes and failures

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I have a friend who lost several dozen koi fingerlings to a large heron a while back, even with a net stretched over the pond. Wily b#stard apparently started violently stabbing at any visible fish until they were too grievously injured to move; after which it would gingerly stick his beak through the holes to fish the dying koi out to eat.
In all fairness the koi were quite small and the net-mesh was rather large, ~1.5"? if I remember right.
I suppose larger fish would be rather safe with a net with mesh smaller than their width, though it wouldn't stop a heron from trying to stab at them.

I do recall he used high-pressure (?) motion-sensor sprinklers around the pond after the incident, which apparently served as a suitable deterrent for the bird as it was met with a wingful of water every time it attempted to land. He also had an issue with racoons attempting to snatch up fish by sticking their handlike paws through the mesh, but the pond was deep and large enough to grant the koi sufficient room for escape; they were also deterred by the sprinklers, according to him- though the only indicator would be a random loud "ffsshhhhhh" in the late evening.
Haven't met the fellow in a good while, though, so I don't know how well the system's held up over time.

I am awfully fond of herons and the like; they seem quite majestic in their gliding flight and slow, delicate struts around a given body of water. There is one that frequents this small pond I occasionally fish at, and it has gotten accustomed to me lobbing smaller sunfish some metre or two away from him to give him a quick meal. Though I do find it mildly irritating when fish take a liking to the aquarium captives we so often maintain outdoors- as a very young child I had issues with magpies trying to get at a few goldfish in a plastic washtub I kept outside; short of covering it I could not find a way of keeping them or their droppings out.
 
Sorry for your loss, I know how much you liked those goldies.
I lost a good number of koi grow ons last year to a heron landing in my garden and walking up to my pond.
Now I live on a street with 40 houses, next to ten more streets with just the same. This isn’t the states, it’s the uk , so my garden is 60 ft x 40 ft and my pond is only 10 ft square although 6 ft deep. This thing strolled right up onto our decking by the pond, 10ft from our house door , jumped onto the rail round the pond and dove straight in head first. Again and again and again until I noticed less and less fish and caught him on camera doing it. I own a dog, and a cat, and live in a neighbourhood of dogs and cats. I’m sure The herons round here have got wind that they are an endangered species and it’s illegal to harm them in the uk, cos they just don’t give two hoots. Now I have balustrades all the way round with 6” gap netting stretched over the full thing.
 
Not about to spend a fortune on this, and absolutely won't net across the water. I'd go back to having no large fish in the pond before I'd do that. I originally envisioned the ponds as a fishless natural water body and I enjoyed watching the insects, frogs, and other critters The only reason I even started to keep fish in there was as a mosquito control measure; for years, the pond contained only Rosy Reds, Medakas and other fish too small to attract unwanted attention. I had a couple visits from a Belted Kingfisher, who took a couple of fish, but there were hundreds in the pond at that time and many of them were eaten by that bird and others, as well as predatory water insects, snakes, etc. Never made a dent in the population.

These bigger fish were different, more individual than just a giant school of squirming tiddlers, and much more attractive to ne'er-do-well fish-stealers. Silly of me not to see this coming. When I noticed a few missing I should have reacted immediately.

Today I picked up a pole-mounted sprinkler system with a motion-sensitive activator. I was playing with it this afternoon; my domestic water supply is much lower-pressure than city water pipes but it can still squirt water all the way across the pond corner to corner. There is no way a predator won't be sent running when this thing goes off. Duke loves it! I'll likely just install a new outdoor faucet dedicated to this thing, and then bury a garden hose just under the lawn running to the pond to power the sprinkler.

Again, no rush; nothing left to protect this year. :(
 
Any chance the parent goldfish may have left behind some late eggs and thus some tiny dull fry the bird missed?
Yes, I suppose I should have stated that it now appears devoid life. Like the past couple summers, the goldies spawned prodigiously this year, using the jungle of cattails in the corner rather than the floating tangles of Hornwort that have been largely absent this summer. With less cover, the resulting fry have suffered heavier-than-normal losses due to predation, parental and otherwise, but there are still several dozen in there up to an inch in length.

The Golden Horde will return!!

View attachment 1565941

Just get one of these to patrol the pond, problem solved
Believe me, if I lived in a more amenable climate for one of those, I'd have one already! :)

I do recall he used high-pressure (?) motion-sensor sprinklers around the pond after the incident, which apparently served as a suitable deterrent for the bird
I set mine up yesterday and it works like a charm. I'm digging the trench and laying the hose into it today, so next spring it will be ready for action.

If the heron returns...which seems unlikely as my stock tank fish are mostly small and not easily spotted from overhead...his protected status will not save him if I see him on or approaching a stock tank.
:swear: 🪓🔪🗡️⚔️💣🪃☠️
 
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The war is on! Then again, that glutton of a bird deserves it. Surprised it could still fly after gobbling down 26 good-sized goldies.

Would you consider keeping a few indoors year-round?
 
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The war is on! Then again, that glutton of a bird deserves it. Surprised it could still fly after gobbling down 26 good-sized goldies.

Would you consider keeping a few indoors year-round?
I was amazed as well, could tell he was pretty much at maximum load capacity when he took off, very laboured flight. A GBHeron is supposed to weigh up to about 5.5 pounds, and I am sure those goldfish totalled far more than that. Makes me wonder if there were more than one culprit involved, or if the same bird visited several times that one day.

Mind you, I have observed other birds lifting up with prey in their talons that weighed at least as much as they did, or more. An Accipiter -family hawk can strike a prey item nearly its own size in the air, grapple it and continue flying. It was obvious they were working hard, but of course the payoff was huge for them. And of course they were clutching the entire weight in their talons, whereas this bird had already swallowed them.

I'll tell you one thing: as pissed off as I was and still am...it would have been ten-fold worse if the dang bird had horked up one or several of all of those fish as a result of being overloaded. :(

Yeah, I've kept a number of goldies inside through last summer, just to compare them to their outdoors siblings at season's end. The outdoors fish were bigger and far more vibrant in colouration compared to their indoors brethren...so of course this year I put all my eggs into the one basket...outdoors.
 
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