what is eating my koi?!

13 years ago

Normally during the winter I can see the koi in the center of the pond, under the waterfall, barely moving for hours due to the cold temperatures. Monday morning I looked outside my window and noticed all 10-12 fish missing. ZERO seen. I run outside and check the filter. 4 fish lay there dying in the filter (we have never found even the smallest fish in the filter, for the large koi to go in there they were surely desperately looking for cover). One 12" koi covered in blood. The large 16"+ koi had his fan tail side fin ripped off. Surprisingly I found the fin OUTSIDE of the pond on the brick! He looked like he was poked in the head. Being the largest fish of the pond but severely beaten up, I was almost positive it was because a heron was not strong enough to lift him out. So I nurse the 4 fish back to life. By the end of the day all 4 seemed like they would live, not sure how long til the stab wounds would become infected and lead to death, but at least live for a little. I then secured the net a little better before bed. I wake up in the morning. SAME PROBLEM! I can't see one fish from our second story window. However, this time I check the filter but there are no fish there! I figured they died and got sucked into the filter, but that was not the case. I walked around the property and did not find any remains. It started snowing at 6am, so by the time I noticed they were gone at 9am, snow covered the ground. There were no animal tracks so it had to occur between the hours of midnight at 6am. We are completely dumbfounded how the net did not appear disturbed. Originally I figured a human stole the fish, but they would not have injured the fish, then returned a 2nd night to get the larger, dying fish. I feel as though a raccoon would have left scraps. A cat would not venture into the water either. Now comes the crazy part. We call my neighbor because he too has a koi pond. He tells us that 2 weeks ago all 30 of his koi disappeared from his pond!!!!! He said originally he figured a human as well, but his dog would have noticed. They he mentions that it may be a weasel or mink! Now living in south central PA (south of Harrisburg) I was unaware that there were minks in the area?? But it makes sense because they could swim in the water to get the fish. However it still doesn't explain why we didn't see any scraps other than the fin of the large koi. Could a heron clean out 2 ponds worth of koi or have you heard of minks eating koi in the middle of winter. Also would a heron feed at night?? Ughhh this is insane.

Featured Answer

jkrudden

13 years ago

I am so sorry. We had a clear pond where we could see all 7 koi 3 weeks ago.. Now the pond is cloudy, We found a pool of blood outside the pond. A few days later a whole fish intact surfaced floating. The pond is 58 degrees the filter is running . All water tests show the water is in good shape. I can't see a single fish. It is cloudy and green so I have treated for that, still nothing after 4 days. So upset we do not know if there are any fish left inside the pond. How can we tell if there are or not? (LOST)

Sort by:Oldest

Comments (13)

carolyn18810
13 years ago
There are birds that feed at night that live in the Northeastern part of the country. Also, bear in mind that during this time of year, birds are starting their migrations so birds that are not from our areas, could very well be passing through.

My question to you - on the second night, what type if disturbances did you see with your netting?

I am also wondering what you and your neighbor typically do to dissuade blue herons from invading your ponds? I have found that a sensor sprayer does a lot of good - however, given the time of year, it seems early to put out a sprayer.

Here is a link that might be useful: Black Crowned Night Heron

This post was edited by carolyn22 on Fri, Mar 8, 13 at 9:23
Related Professionals
Mobile Landscape Architects & Landscape Designers · Bainbridge Landscape Architects & Landscape Designers · Houma Landscape Architects & Landscape Designers · Greensboro Landscape Architects & Landscape Designers · Spartanburg Landscape Architects & Landscape Designers · Danbury Landscape Architects & Landscape Designers · Manchester Landscape Architects & Landscape Designers · Sheboygan Landscape Architects & Landscape Designers · Atlanta Landscape Contractors · Vincennes Landscape Contractors · Lawton Landscape Contractors · Temecula Landscape Contractors · Athens Stone, Pavers & Concrete · Harrisonburg Stone, Pavers & Concrete · Montréal Stone, Pavers & Concrete
Steph79
13 years ago
Maybe use a game-cam to see what it is? We just put ours out to see what's been messing with the fish, and have seen a couple of pictures of a cat coming around.
lisalockwood22
10 years ago
Just cleaned my pond and all my koi are gone! All of them! No sign of anything wrong until we cleaned the pond today. I had over 50 koi of all sizes. Someone said maybe a mink ate them. We had kept the net on the pond all year to keep the heron out. Now this. So upsetting. How do you keep a mink from eating your fish?
akarinz
10 years ago
last modified: 10 years ago
So sorry to hear about the loss of all your koi.

I'm not familiar with mink, would they get under the net?

My first pond was 2.5 feet deep. I lost several fish to predators. That pond has been rebuilt to 4 feet deep, I haven't had any more problems.
lisalockwood22
10 years ago
The critter put a hole in the net.. Someone else thought it might be an otter.. They said to buy critter litter to help keep the critters away. I'm not familiar with that but I'm going to look for it.
akarinz
10 years ago
Several years ago, when my pond was shallow, I had problems with herons. I ended up having to put chicken wire over the pond.
lisalockwood22
10 years ago
i've had a net over my pond for that reason for over a year. i'm told it's a mink eating my fish. i'm setting a trap tonight.
Momothegardenhoe zone 5, Central NY
10 years ago
A mink ate all the Koi and goldfish we had in our pond this past winter. We keep a bubbler going which creates a small hole in the ice. We actually saw the mink swimming under the ice, so I waited near the hole and he came up with a #%^@&# fish in his mouth! I even caught it on camera! Now I have to figure out how to post the pic, lol
lisalockwood22
10 years ago
I bought a camera but haven't seen anything yet.
Hilde Gard
10 years ago
It's sad to read about so many beautiful fish killed like sitting ducks in people's ponds. Why don'tt the businesses selling the fish and pond set-ups warn people about all the known hazards? ???
BarbJP 15-16/9B CA Bay Area
10 years ago
Why scare off potential customers? After all they can sell them more koi afterwards. Problems are what koi clubs are for.

I have heard of folks losing fish to weasels or minks. Unfortunately, short of a sturdy, tall metal fence or trapping, there's not much you can do about them. Trapping is regulated by state and county, if someone goes that route be sure to know all your area's rules.

I've very grateful we don't have those critters around my area.
Steve Walsh
5 years ago
This the 2nd time Ive been cleaned out. Pond is 5×8' and 4' deep. No sign of it being except it left a little calling card. Might be a fisher cat (I ve seen them around) or a weasel which this turd is about the right size for. Now what to do about it?