Tuesday, April 14, 2009

Did the Mallard Ducks Eat My Koi & Goldfish?


A customer from Aquatic Connections emailed me the following question when she discovered that the fish in her pond were missing: We had quite a few fish in our pond, however, I was leaving for work one morning and noticed we had ducks on our pool cover. Do you believe the ducks probably noticed the pond and went fishing? If so they ate many of our gold fish and koi.

This was my reply. Every March & April we have a pair of mallard ducks show up in our backyard. If there is water on our pool cover, they like to hang out there. I usually send the dog out to scare them away. The cover is messy enough with all the leaves and debris, I don't need the ducks adding to the muck.

Sometimes they decide to swim in our pond. It's always a male and a female mallard and I often wondered if they would ever nest in yard. Anyway, they just swim around and bask in the sun until I send out our dog. Over the last five years they have visited our pond, I have never seen them eat any of our koi or goldfish.

So I did a little research on the food preferences of mallards and this is what I found out (courtesy of CentralPets.com):

Not overly disturbed by human activity, Mallard Ducks are often seen in canals, lakes, ponds, and urban parks. They seem to be able to adapt well to nearly anywhere with a body of freshwater and an appropriate climate. Mallard Ducks are migratory, spending winters in more southern regions and summering in northerly parts of their range. In warmer areas of the world, some Mallard Ducks may not migrate. In the fall and winter, they pair into mated couples. Although females quack, males do not; rather, they communicate with whistling or grunting noises. Mallard Ducks spend most of their time foraging for food. They eat a number of items including insects, fish eggs, small fish, tadpoles, wild rice, berries, leaves, green plant shoots, and grain. Most of this food is acquired from foraging in muddy areas in or near the water and embankment of the Mallard Duck's home. The Mallard Duck uses its bill to filter food from the mud.

I think most koi and goldfish would be too large for the ducks to eat. Something else may have eaten this customer's fish. My guess would be a heron. If you have had a similar experience with ducks or herons or disappearing fish, please post your comment for us to read. Thanks.

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18 comments:

Anonymous said...

The first spring I had my pond (aprox.2000 gals.)a pair of mallard ducks took up residence. Several days later I noticed a nest with about 14 eggs.

Anonymous said...

Have they eaten your fish or otherwise wrecked your pond? We have a pair hanging around our pond which is approximately the same size as yours, and I'm trying to decide how seriously to attempt to make them relocate. I'm taken with the idea of cute little ducklings, but don't want the pond ruined...

Anonymous said...

The mallard pair left the pond I beleive because of our spring activity.I found the nest with eggs a few days later. I think ducks eat plants.

Anonymous said...

The ducks have never done any damage to my pond.

robin601 said...

I watched from my kitchen window, a female duck chase and catch a 4" long goldfish from my pond. She was sitting on the side of the pond with the fish in her beak when I rushed out there. The fish was dropped when she flew off and now it still swims around with a white patch on either side of its belly.

Ed said...

Mallards are dabblers. They eat aquatic life and insects - bread crumbs and corn. I have a pair in my pond now. This is the third year that they have arrived in the spring and this year I will let them stay. I have two concerns: (1) they stir up any silt on the bottom when they feed with beaks - making the water murky and (2) Mallard guano. In any case - I will not chase them away this year and see how it goes.

Last summer - I did have a Black Crowned Night Heron (here in Minnesota) decimate my pond. It took me a while to figure out what was going on - but one night at 2 am I went out with a flashlight and found the BCNH sitting on fence watching (fishing) the pond. After this encounter - I strung mono-filament line in a web pattern across the pond (about every two feet or so) and I have not lost a fish since.

david 8 said...

I've had two mallard ducks on my pond all week which I thought was great until this morning when I went out to feed my fish only to find that there were none there. Either the mallards had had them or we have had a visit form a heron - some of them were over 6in long!

Anonymous said...

I had a pair of mallards show up at my pond, and all my fish appear to be missing too.

mo said...

@ Mallards showed up in my pond...I had the kids outside, I was taking pictures, it was SSSOOO cute....till I realized a day or 2 later we had misplaced 40-50 goldfish.....
I was welcoming them for god sakes...

They may have a little surprise next time they show.

Anonymous said...

Keep in mind that it is illegal to disturb waterfowl here in PA. Deterents like dogs, sprinklers, things like that are probably better. You can call the game commission to ask for advice. I have too many small goldfish or interbred koi/goldfish, and was wondering what I was going to do about this problem. My resident Mallards don't seem to have depleted the supply at all. My pond is designed to discourage other predatory waterfowl with the deep end being very deep and straight sided.

I've been much more concerned about what impact will their droppings will have on the ecosystem of my pond. I would think they would feed algae--always a problem in cooler weather.

Anonymous said...

I've had a Mallard and six ducklings for the past month or so, at first they were cute...until they ate every lilly on my three plants a fourth plant is totally missing they even uprooted and ate that, after they come it looks like a 12 foor cesspool. This is there new home and the ducklings will be back for years to come. I pulled out my plants and drained the pond a put everything into storage. I am very sad about this, but I never imagined it would turn into a DUCK POND. I need to think of plan B. Mike

Anonymous said...

We have had chickens for years and last spring got ducklings. This summer we put in a pond specifically for our ducks. What fun! We knew it wouldn't be pristine and we use irrigation water that constantly flows. We love it. A neighbor offer to give us some goldfish. We might try a few. We have 5 ducks now. Very entertaining!

Anonymous said...

Mallards might eat fish that are the size of anchovies or smaller, but they ignore the fish if there are other things to eat such as worms and vegetation. Fish are hard to catch! They don't and can't eat larger fish simply because they couldn't catch or even swallow them. They love duckweed and sago pondweed, if you're looking for pond plants that can provide them year-round food. A few mallards in a backyard pond won't create any problem with their droppings--if you plant the duckweed or sago pondweed, the duck droppings actually feed those weeds and create a nice ecosystem overall.

Anonymous said...

Ok I have been fishing for over 25 years and I have never once witnessed a Duck eat a fish. Im sure it happens from time to time but as a rule I would not worry about ducks. It is far more likely that a heron or another type of bird is eating the fish. Or it could be a snake or a raccoon.

Anonymous said...

I had some mallards nest next to my pond, and they grew fat but have always been perfectly civil. Some darker much larger ducks now hang out with them, and they have eaten all my beautiful lillies and snatch up unwary mollies. My koi is now covered in injuries. I do not believe that mallards are harmful, but if you see different ducks, be wary.

Anonymous said...

We made a big sized fish pond in the back yard with a bridge over it and all. Towards the end of summer we added two beautiful white crested ducks. Now we're finding out our little fish are gone. I did not believe that the ducks ate them until I saw one with my own eyes tring to gulp down one of the bigger ones. The duck acted like it was a real delicacy. So much for our fish pond with ducks. (:

Anonymous said...

Iheard a friend lost their goldfish to Mallard ducks, they wittnessed it. I have a huge pool turned pond full of Koi and goldfish. 12 years now and my problem is too many fish! I have had run ins with Blue Heron this year I stuck a few scare crows around the pond and launched a kayak! The heron hasn't been back but now the frogs are singing away, mating and driving me nuts!

Anonymous said...

I just watched a mallard drake actively hunting the goldfish in my small pond. It was leading with it's bill and very aggressively diving - completely under water for 10-15 seconds. Since my pond is only about 10'x12' and 2' deep, I could see the drake chasing the fish around underwater.