My koi are acting strangely scared

[Tsuska]

Hey guys. I got home today to find that my pond was devoid of my 11 koi. Upon closer inspection I saw a few hiding behind and around the pots. Normally they rush out to greet me. So I tried to encourage them to come out by feeding them. Eventually they realise there's food and they all come rushing out to eat. Well 10 of them did. And they came to eat eat eat quickly and then vanished again into hiding. I haven't seen my largest koi though who is about 12 inches. The difference between todays weather is that it's much warmer/hotter than the previous few days (which was overcast or raining a bit) We're at the end of spring at the moment so temperatures have been quite warm anyway.

I also have a net around the pond and it seems undisturbed. Any idea why my fish are acting that way? And i have no idea where my largest koi is...hopefully he's just hiding...

 

[Waterbug]

Cane Toad attack? Dingos? OK, I don't know what kind of predators you have, but that would be one guess. Although fish seem to get back to normal pretty quick. When you say net around the pond, do you mean like a barrier nothing can get through? Predators can be very resourceful.

Assuming your fish shows up you could test KH just to be sure there isn't a pH issue. Have you been getting a lot of rain.

Spawning?

 

[Tsuska]

Hmm haven't seen any cane toads where I live and no dingos. The net is just a bird net so it's not a perfect barrier but it covers the entire surface of the pond (about 30 inches above waterline), It was there to prevent a preying kookaburra from attacking. I tested my pH, still the same as before (around 6.5). Hmm maybe we'll see what happens in the next few days...maybe they have been spawning but i don't see any eggs.

 

[addy1]

I was battling a heron for a month or more this summer, they are very patient and do not give up easily. I don't recall how deep your pond is, mine is deep enough the fish can dive and get away from the bird.

Is there a place a bird type predator could stand at the edge and reach into the water? That is how a heron fishes. Well mine also flew over the fencing and plopped into the pond, which is not how they normally fish. My fishing line snagged the suckers feet as it plopped all fish survived lol.

I had to look up kookaburra, the web sites they are carnivorous, but they don't list fish as part of their food. But then why are they also called kingfishers................humm lol, but when you look up kingfishers they do list fish as part of their food.

 

[Tsuska]

My pond's about 3 feet deep at the deepest area but some areas can get quite a bit shallower. Now that I think about it, there is one are where a bird could stand a 'fish'. We have Australian White Ibis i guess, though I have not seen any around my area recently. But then again they're everywhere in Sydney. It could also be my neighbour or one of my neughbour's cat...although I haven't seen him around since I scared it off (when it was suspiciously sitting in the aforementioned area). If the Ibises have been around that would be troublesome...but I didn't think their beaks could reach far enough as long as my fish could swim away quickly.

Kookaburras definitely eat fish and there's at least one little buggars territorially hanging around my house all the time. And they have a crazy sarcastic laugh...(look up kookaburra laughing on youtube) But i'm pretty sure it can't get my koi anymore because of the bird net. Hmm need some detective work...

 

[addy1]

If you think it is something walking up to your pond, put some sand around if you can to get some foot prints.

I caught the heron before it could snack on my fish, just because we had installed security cameras, not to catch thieves, but to watch nature and the pond...............well my camera alerted I look up and see a heron casually walking up to the pond. up went the chicken wire, then when it dove in the pond, I put one piece of deer netting over the pond to make it so it could not fly in.
The best deterrent has been the alligator heads floating, a natural predator of the birds. The heron does not like them at all.

We had seen a small bird visit a few times, but it never stayed long and never got a fish.

They make some nice cheap ip cameras you could install that would send pictures to your computer so you could see what is coming by.

 

[sissy]

you said yoour ph is 6.5 that is low for koi I keep mine at 7 or 8 it's not low enough to cause that .Do you have an aerator to give the fish oxygen as the temps go up and down it could be confusing them .My pond is in direct sun and monday it was cold and windy and did not get above 40 degrees and yesterday it was a little over 70 degrees and my pond is in full sun and the fish were hiding from the sun yesterday .They did come out for food though Something must have scared them .I had an owl that scared my fish but after I put up the flagpole and flag near the pond the owl did not come back again .I guess he does not like the flapping noise and the movement of it

 

[anitapond]

Here's a little "detective" story for you. I have my pond netted 24/7. I suffered a coon attack once and it was devastating. On a daily basis I see opossums, herons, coons, hawks, cats, and many other animals, but the others aren't fish eaters. Several weeks ago I noticed 4 fish were missing from my pond, completely gone, no remains, no disturbances. I couldn't figure out what happened. The mystery was solved when I went out to feed the fish one day and saw a snake slithering in the pond, on top of the plants. Then it hit me - snakes are about the only fish-eating animal that could fit through the netting. Like herons, they are very patient and wait patiently for the perfect opportunity to strike. They actually put their heads under the water to grab fish, leaving nothing behind to find, and disturbing nothing in the pond during their hunt. The snake that was (or is?) in my pond was a garder snake - not a "water" snake. On that note, if anyone has any ideas to keep snakes out of a pond, I'm all ears!

 

[sissy]

You could put eggshells as snakes don't like the roughness but they may bring other animals .Here some break up oyster shells after the eat the oysters and put them around the pond .

 

[Waterbug]

Unfortunately a pH test doesn't tell you much, just what pH is at the moment. It normally changes throughout the day. With a pH of 6.5 I would assume KH is very low. Couple that with a heavy rain (Sydney rain is about 4.3 pH) and the Koi could be stressed. KH level provides the answer.

Low KH could hurt ammonia conversion as well.

I have no idea however. Very hard to guess at these things.

Did the missing Koi ever appear?

 

[sissy]

I have snakes here and I bought what is plastic barbed wire it has little plastic teeth sticking up and all around it and guess the snakes do not like the prickly feeling .Not sure where I got it from but remembered it did say it was a safe and non toxic snake repellant .I will have to go threw all my books and see if I wrote it down .Could have been a farm store like tractor supply or southern states .

 

[HARO]

Tsuska; no cane toads or dingos, eh? Maybe a saltwater croc hiding in the raupo! :ugh: John

 

[Tsuska]

Hahaha, I don't think there's a croc here =P. Snakes...maybe, there are a lot of snakes in Australia. Haven't seen any around my house though. I live in sydney suburban area and it's actually quite busyish where I live so wild-life is usually confined to a lot of birds and lizards, horses (okay their not wild), domestic pets etc. Well today I found my big Koi who finally decided to come up and eat as well but they still seem terrified of something...including me. They stay near the bottom of the pond unless coming up to find food, they stay in a bunch a lot more than they used to and they seem to dart around the bottom of the pond around the pots...they don't act sick or lethargic or anything.

I know my pH is lowish but it has always been low...and I don't have anything yet to measure KH.

There is one main thing that has changed...I've recently turned on my UV clarifier for the first time and the water now is clear...(with a brownish tannin tinge from all those leaves...time to get out some activated carbon). Maybe...just maybe...they're not used to clear water? Then again the water was relatively clear when I first introduced the fish to the new pond.

 

[Waterbug]

Glad the Koi showed up.

Yes, suddenly clear water certainly could make the Koi hide. Unclear water hides them and now they're the center piece on the dinner table. Unclear water also offers UV protection so that could be stressing them too. If this is the cause they should adjust shortly.

Even if unrelated to the current behavior you might consider reading up on "pH buffering" and why KH is important. It is something that can kill fish, so worth a read. It's pretty simple. If your source water is low pH too, you should also read up on GH. Most people can ignore GH as they can plenty from their source water, but you may not be in that camp. After you understand KH and buffering you may not feel you ever have to test pH again.

 

[Tsuska]

Alright thanks. I will look into pH buffering. This is the water we should be supplied with according to Sydney water: http://www.sydneywater.com.au/Water...lysis/WaterAnalysis_PottsHill_2011.pdf#Page=1 (Potts Hill water, the far right column)