:( My fish are disappearing. I had Koi and Goldfish, now I'm only stocking goldfish. One day there were 7 koi, the next day only 4. The same is happening with the goldfish. There are no herons in Bergen County New Jersey so I am really perplexed. I searched the bio filter, under the plants and between rocks. They simply disappeared. Any ideas, recommendations?

how big is the pond? is it possible that your other koi at your other fish? It could also be other predators such as racoons or cats.

My pond is 19' x 21', 18" to 36" in depth. How can I tell if the fish are eating each other? Won't there be remnants?

I've never seen racoons in our neighborhood but there are a number of cats that stroll through my yard and occasionally a skunk. They would have to go into the pond to get at them. Is that likely?

This may be a little crazy, but I'm considering a hidden video camera. For all I know it could be a neighbor.

do you know how many gallons? If you built your pond right the cats and racoons cant get any fish. You should use a video camara. If the other fish are large enough to eat the other. Like you have full grown koi and you just added some babies. i dont know if they would do that but any things possible.

I had that problem, with fish "disappearing" I know the other fish werent eating them, the are all roughly the same size, but then I found peices of fish, or fish missing peices of themselves... as in I had a fish with no head, or a fish with the back eaten out of it, i figure it was either a cat, racoon, or opossum or something along those lines

but if you build your pond sides on an angel those animals cant get to your fish unless the fish are stupid. Or if you have a shallow or small pond.

How do you know it's not a heron? If fish just vanish (no remains), it's often a heron but could be a hawk, owl, or person. With parts left, it's often a raccoon or cat. Opossums, foxes, etc. rarely get fish.

My page on birds that prey on pond fish - http://www.fishpondinfo.com/birds.htm
My page on mammals that prey on pond fish - http://www.fishpondinfo.com/mammals.htm
A section on "Where did my fish go?" (see under ponds): http://www.fishpondinfo.com/health4.htm#where

A camera may work but it would have to be in just the right position. Predation often occurs as dawn so maybe you could get up early one day and watch the pond at day break.

How big were the koi? If they were small, they may yet be hiding. I hope so.
Larger fish will eat smaller fish. Normally, there are no remains if the entire fish was eaten. How big were the big koi and how big were the small ones? Koi don't usually eat each other but may eat fry (under an inch).

Your pond is a good size (bigger than mine it sounds like). I thought my pond was predator proof but I was totally wrong. Both raccoons and herons frolic around but a net keeps the herons from the deep end that was supposed to be too deep for them to stand in. Steep sides do NOT stop herons and raccoons. I have a foot drop off around my pond. I guess my fish are also "stupid" as they will go into the shallows where the net is not and get eaten by a heron. Goldfish especially love to spawn in the shallows in spring, and the herons benefit. I try to keep the net on the shallows now in spring but eventually for the plants to grow, it has to come off.

If the neighbor is suspect, then I would put a sign by the pond that says GOTCHA! with a picture of a video camera on it. I can draw it up for you and you can print it out. :) If the fish are back the next day, at least you'll know it wasn't a raccoon that took them. :D

why would your neighbor want your fish?

Some koi are valuable. Then, of course, there are just nasty people.

You are all so wonderful to share with me your advice and experience. I have found no fish pieces and all (about 15) are comets sizes 3" to 6". The perimeter is surrounded by large boulders. I am thinking of raising the perimeter with another layer of boulders to deter cats and racoons. But Owls? We do have them because I hear their hoots but I've never seen them. They could be the problem.

Robyn thanks so much for the links on fish predators.

im interested what this could be. you should try a video camara if it starts happening again.

You can print this out and tape it by your pond, Rand. It might be easier than a real video camera. :)

hey thats good margo :D .

I wouldn't have thought that owls would take pond fish but at least 2 or 3 people over the years have e-mailed me that indeed they have caught owls in the act of taking fish from their pond. One was a great-horned owl who would take his goldfish up into the tree to eat. That person eventually netted their pond.

my neighbor has alot of trees and stuff in his back yard along with a small pond. We noticed fish started to go missing and then one night we saw 4 barn owls in the trees. it could have been them.

Thanks Tom. :D

its very interesting please find out who/what is doing this.

Ya know, you can always round up the usual suspects: owl, raccoon, snake, opossum, neighbor, heron and cat, but you never know which one is the guilty party. They all have poker faces. :D

if she found them in pieces its probaby the owl, racoon, opossum, and the cat. But i dont under stand why you could see the pieces. i thought they would take it to there home and eat it?

Yes, you would think that's where they'd eat it. But, knowing animals, they can't wait that long. :D

i must know what it is!

:D

i think it may be a racoon.