Otters raiding garden ponds

There are an increasing number of cases where otters are taking goldfish and koi from garden ponds. Otter numbers are on the up, and they are on the look-out for food. They might already have taken some of your fish, when you blamed a heron.

What is the real level of risk to your pond and can you do anything about it?

The otter increase
Otter numbers in the UK had dropped very low by the 1970s, partly due to the effects of certain pesticides. Since then, due to safer use of agro-chemicals and deliberate protection measures for otters, their numbers have steadily increased.

In our area (Severn Vale and Cotswolds/Upper Thames) surveys between 1977-86 found no sign of otters across all 114 sites checked. Yet by the survey of 2009-10 otters were found in over 60% of those sites, a remarkable recovery[1]. Numbers have continued to increase since then, and there are reports of otters in virtually all English river catchments now. There are healthy populations of otters in Wales and Scotland too.

Garden pond raids
From my own experience in our locality, I had only been personally aware of two possible cases of fish being taken from the late 1980s up to 2013. One of those was from a large pool close to the River Coln, where otters were suspected. The other was from a fish stockholder, where mink were the most likely culprit.

However, I now know of at least seventeen cases since 2014 where otters have been confirmed or suspected. These occurrences have been in three distinct areas, two in Gloucestershire (Minchinhampton, near a small tributary of the River Frome; and Cheltenham, near both the River Chelt, and Noverton Brook), and the other in North Wiltshire (one near a feeder stream for the Cotswold Water Park, and the other on a tributary of the River Ray near Swindon). It is noteworthy that ten of these cases were in town centre gardens, some up to 500m from the nearest stream. There have also been reports in newspapers of otter attacks on garden pondfish in a number of other parts of the UK.

How would I know if otters had been in my pond?
Otters will often visit between dusk and dawn (though feed during the day too) and most customers affected have been aware that something had happened by the following morning. In some cases substantial fish remains have been left partially eaten at the pondside, with large chunks removed from koi. Even big koi (60cm plus) have been taken. In many cases virtually all fish have been killed or eaten on one visit. In other cases some large koi have been left in the pond with severe wounds to the body or fins. (This is unlike heron attacks, where fish over 50cm are less likely to be taken; wounds tend to be spear shaped or in parallel markings on each side of the body; and where many fish escape, frightened into the depths.)

Otters are substantial creatures with brownish coats, and can be a metre long. They are capable of dislodging stones at the pool edge, and knocking planting baskets off the pool shelves – one customer was convinced that the damage to the pool edge could only have been done by a human… until they saw the otter swimming in the pond.

If otters have been in the area, they can leave patches of their distinctive tarry waste (spraints) on nearby rocks/paving. This has a strong, slightly floral odour and may have scales and bones in it. This is unlike mink which are smaller (up to 60cm long), with much darker coloured coats, and whose waste (scat) is tubular, just over an inch long, and smells unpleasant.

Is my pond at risk?
If neighbours have had otter problems then you are most definitely at risk. Otters can travel many miles within a territory, and may not return to an area for some months, but they are likely to revisit. From the reports I know of, if you are within 500m of a stream or river, then your pond is at greater risk. If otters get a taste for garden pondfish, then perceivably they may, like foxes, look further afield in towns and cities for food.

What can I do to keep otters out?
It is uncertain what alerts the otters to the presence of garden ponds, but they are known to have very good senses of smell and hearing. Perhaps they can hear garden waterfalls and fountains, or maybe they can sense the traces of fish aroma coming from the pond surface. It certainly won’t help to leave fish food (pellets or sticks) outside near the pond, as these have a strong smell.

Angling fisheries have had increasing problems with otters, notably on carp fisheries, and suspect that reduced numbers of wild fish in some streams (possibly due to predation by cormorants or signal crayfish), and increasing densities of otters, might also be driving otters to look further afield. Fisheries have had to take substantial steps to keep them out. Certain designs of heavy-duty fencing have worked, usually in conjunction with a powerful electric line (the thick otter pelt gives them some protection from lower powered types)[2]

Ordinary pond cover-nets and heron deterrents (see the post on Herons) are unlikely to have any impact. Wire mesh covers may help, but are of course very unsightly.

A few customers have been so upset by an otter attack that they have decided not to restock with fish, whilst others are taking a chance and restocking with a few low value fish. There is no doubt that otters will impact pondkeeping in future, with at-risk ponds less likely to be stocked with ornamental fish.

Useful links
[1] Environment Agency Survey (pdf)
[2] Fencing to keep out otters (pdf)
Telling the difference between otter and mink
Conference Report on Otters and Fisheries (2012)
Otter fact sheet


17 thoughts on “Otters raiding garden ponds

  1. We have lost one or two pond fish over the last couple of weeks. On each occasion, the fish head was left on the lawn next to the pond. We tried to protect the remaining dozen fish by netting the pond. However, this morning we found three destroyed fish remains and all remaining fish gone. Originally we thought it could be mink but now realize it may be otter. We are about 1000 meters from a small river tributary.

    • I just posted my story yesterday upon actually seeing an otter emerge from my garden pond in the early hours. We live in Fife, Scotland in a village on the main road and have had the pond for over 30 years now with only concerns over seagulls and herons so have several nets which have extremely strong netting fixed onto aluminium frames. We chose the aluminium frames over the steel ones to make it easier for lifting when necessary which unfortunately made it easier for the otter to squeeze under so now we have a series of heavy stones and stone garden ornaments placed to firmly hold the frames down! The pond is positioned in the front garden of the house so we could keep a very close eye on it, however had it been in our huge back garden, then I would never have seen the otter emerge in the very early hours of yesterday morning. At first I though it was a cat in the pond until it emerged with its short legs and built it was easily identified in the strong security light I had switched on. I still find it hard to believe and wish I had got a photo of it but the shock of seeing it, then finding my once beautiful, mutilated fish with a hole in their bodies where the kidneys and liver had been ripped out of still shocks me. My neighbour 4 houses away has a large deep koi pool with no netting so I am going to tell him to beware. I have no idea if I am the only person in Scotland to be targeted but I am sure there may be others. The otters you see on the TV look so cute but in reality they are a vicious and wasteful killer only eating the liver and kidneys, occasionally the head and a chunk of the body. For some reason it left 2 lovely fish in the flower beds unmarked just to die for the hell of it! Not a great idea to introduce it again, as in the past it was hunted for its destructive behaviour. This is my opinion and I am a caring person who rescues unwanted animals and am always picking up wild animals and birds in need of help to take to the SSPCA.

  2. I spent several hundred pounds on orfe, carp etc in March only to find an otter present within days. I had previously not seen an otter but a river runs literally yards from the pond. Whilst l lost most of the gold en orfe a small shoal has survived and I have not seen the otter for two months. I have not seen any carp or koi since. I think the otter must have got scent from the newly introduced fish. Will now consider stocking with orfe, possibly Rudd but definitely not expensive or ornamental fish.

    • Sorry to hear this. The research I’ve seen shows that otters vary in their hunting patterns for fish types and sizes, with no clear preferences. It will be revealing to see which of your restocked fish fare best.

  3. Just had my pond cleared out after 5 years. No river for nearly 10 miles. All the plants knocked in with slash marks on a Lilly. 3 fish scales left on paving. Wondering when to restock. Kois and orfe. Cromer norfolk

    • I’ve found otters to access areas by relatively small streams and ditches, so no adjacent river is necessary. As they may well revisit, there is unfortunately no guarantee that replacement fish won’t be targeted too. Orfe and rudd can be fast swimmers, so might be a fraction less easy for otters to catch than slower koi and goldfish, though I suspect all fish varieties would still be at risk.

  4. I live in Scotland in a village next to the main road. Last year I bought protective heron nets knowing my fish would be safe from seagulls and herons. The pond is located in the front garden so we can easily check on the fish night and day. This morning I woke at 1.10am for the toilet, sadly didn’t check on the fish then, and went back to bed but couldn’t sleep for some reason so at 2.30am I got up to check on the fish and could see there was some sort of turmoil in the pond. When I put the security light on I was shocked to see a broad, flattish, furry cat sized creature in the pond which managed to struggle from beneath the nets which are fixed on metal frames and then moving very clumsily, escape under my front gate! It was definitely an otter with the way it moved, shape of its body etc. I decided to go out onto the pavement to see if it was still there and sadly I found my best and biggest golden carp lying mangled on the pavement with kidneys and liver removed. I lifted it with a shovel not wanting people to see this sight in the morning and buried it along with a headless 6″ golden orfe I had just had 2 weeks which I noticed at the side of the pond on the concrete. I put heavy flower pots on top of the corner of the aluminium frames and of course didn’t sleep again. This morning I was dismayed to see my beautiful tri coloured carp in the flower bed with kidney and liver ripped, out then a little further on in the same flower bed , 2 large and nicely marked shubunkins, unmarked and just left to die. At .2.30 this morning I did not realise other fish had been attacked and never thought to check the flower beds but I could not sleep, kept looking out at the pond so I am now realising that had I looked out at 1.10am, then I may have seen it busy at work and perhaps saved some of my fish. Herons swallow fish whole and don’t rip the kidneys and liver out which an otter does. What a wicked and wasteful creature to re-introduce which doesn’t make any sense. No wonder they were killed years ago due to their destructive nature. Had the whole fish been taken for a meal then ok, still very sad but not so wasteful, but to leave pure destruction just ripping out liver and kidneys with also 2 fish unmarked but just left out to die has made me so angry! I am now going to do a part water change to see if I can see if any of my fish are still there and put the heaviest flower pots on the frames. Can anyone tell me who I need to get in touch with, as apparently a National pot of money is available for electric fencing to prevent otter attacks on ponds? This morning I am getting something to block the space under my front gate which is approx 4″ high which my cats can’t get under and I was amazed that the otter was able to squeeze itself below it! My neighbour still cannot
    believe I saw an otter but it was definitely one as I saw it so clearly when my strong security light was on.

    • Sorry to hear of your fish losses. The damage sounds like an Otter, though Otters are considerably longer than cats (mink are around cat length). Although Otters were deliberately reintroduced in a few places, that was some years ago and only to a limited extent. The increase in number is more likely to be down to the end of use of certain pesticides, and lack of control. As with deer, the problem comes when the numbers increase to levels that are considered to be too high, but there is controversy over whether and how to cull the numbers. As Otters are a European protected species, I can’t see culling being an option in the near future.
      There is no pot of money for fencing to protect garden ponds. In England there may be limited funds to protect commercial fisheries funded by the Environment Agency from rod-licences, and sourced through the Angling Trust

      • Thanks for your reply. The creature could only have been an otter as it was mid brown in colour and a fair size. The body would have been a bit longer than a cat but it was a chunky animal with very short legs. I have 5 pet cats and all are different sizes from small and petite to a really massive male so when I mentioned length of a cat I was possibly thinking of our Billy! I have seen otters on the TV and definitely it could only have been that. I have seen mink before, but not around this area, and they are a slighter creature altogether so there was no mistake with my identification. We have weighted down the pond frames which are aluminium and chosen by us for ease of moving for access to clean the pond so hopefully that will help. The security light is now set to come on during the night when we sleep as the otter moved as fast as it could when the light was switched on from inside and was already on its way by the time I actually opened the house door. If we still have problems then I may think about getting or borrowing a terrier from the gamekeeper that will sleep in a kennel near the pond at nights to protect the remaining fish. Our large German Shepherd is too soft and sleeps too well to be of use in this instance!

        • Update 29th July 2017

          The day that I lost my fish to the otter, I called at my friend’s house to warn her that there was an otter in the village which had raided my pond. She lives at the south end of the village, one quarter of a mile from where I live and on the edge of fields and has a raised pool with various fish in it. She was very surprised at the otter’s raid and I think she couldn’t quite take it in at that time but I did make her aware of the danger.
          The next day when I called in order to take her spaniel a walk with my dog, she was very upset saying she had been in her kitchen at 5 am and noticed an unusual creature in her garden so went out and to her amazement, saw an otter somehow managing to squeeze under a small space under her gate! She like me, could not understand how it had managed to squeeze under the small space as I did in my garden, when it went under my gate. Since then someone I mentioned it to said an otter was able to compact itself? Later on the day it happened, Sheila could still see her huge carp and one goldfish in the pool. There are plenty of plants and I did say that the others tend to hide away for even weeks after such a raid. Yesterday, 3 days after the otter’s visit to her pool,, she is convinced that the huge carp and goldfish are no longer there so the otter must have returned she thinks. She did take the precaution of nailing a board at the bottom of her gate so it could not get in that way but I did say to her that the netting she had was really insufficient for protection and I think she needs somthing like I have but probably in iron rather then aluminium. I will update again once we know if any fish are remaining in her pond and also when I can ascertain just how many fish I have remaining as I have only seen 3 so far but I am sure there are others hiding.

  5. We have a small raised pond in our garden. The garden has fencing all around but an otter has still managed to get in and eat our fish. The weird thing is we live in the middle of a housing estate near Stroud, Gloucestershire with no running water anywhere nearby. The nearest ruining water is at least half a mile away as the crow flies. The otter was first spotted by us on our front lawn a couple of days ago. It ran off and we didn’t expect to see it again. However, about an hour ago I opened our back door and there it was curled up on the doormat! It had tried getting back into the pond for the last remaining fish. It’s ran off under our decking now so not sure what to expect next!

  6. Fencing will not keep an otter out as I found it can get in a very small space despite it being a bulky creature. The otter, after raiding your pond, is hanging around under your decking hoping at some point, to kill and eat the rest of your fish. I am not sure how you could get it out from under your decking but it seems a very confident creature, sleeping on your door mat!. Metal frames with netting can be sourced online from Harrod Horticultural where I bought my frames. Unfortunately I chose the aluminium frame for lightness to move for pump maintanance and this is the way the otter got into my pond. At the time of purchase last summer, I had never seen an otter except for the TV and rated them cute creatures so the netting was solely for the herons and seagulls. Otters as I have now researched, are cruel and wasteful killers and I will need to buy the steel frames for my netting. At the moment I have purchased lengths of heavy edging stone lying on top of the pond frames to weight them down as I found that even heavy flower pots are easily knocked over by the otter. The stone edging slab cannot be moved so my 6 remaining small fish (otter took my very large pride and joy koi carp and golden orfes) seem safe for the moment and though my once beautiful pond looks untidy with the edging slabs, I am not going to let the otter win. If I continue to have otter problems in the future, then I will consider buying an otter hound to protect my pond and property . It is more than annoying that someone somewhere decides to boost the otter population to the extent that private pond owners and fisheries are being devastated, and sits back without any concerns!

  7. We live in Yate, South Glos, 50m from river Frome. We’ve had a pond for 30yrs and no problems. Two weeks ago our largest Koi, over 20 yr old went missing and there were remains of another Koi. In past week we’ve lost 10 fish, a few each night and even a large Orfe. An Otter is the chief suspect, originally thought it was fox or badger. Would a sensor floodlight deter them?

    • A floodlight might deter an otter for a while, but they can visit during daylight too. One of my customers who had lost fish to an otter has since installed a fence with a triple electric line at the top (using the power source from an electric cattle fence), and that seems to have worked so far.

  8. Woke up on Thursday and thought the pond looked a bit strange as the plants looked scruffy.
    The following day I checked the pond and the water feature was knocked over and lots of damage to the water lilies.
    I have lost over 50 gold fish and there are only a few small rich left . I also found one solitary coloured goldfish.
    I live near the river Plym and I have a small stream in the back garden. Never had any problems in the last 10 years but suspect that there is an otter causing the issue. I’ve bought a camera trap but not sure if it will return now that there’s no fish left.

  9. Live in Frampton Cotterell, South Glos, with a long garden that backs into the river Frome. Have a large formal Koi pond and have recently lost 7 fish up to 14″ in length over a 1 week period whilst pond fully nylon netted. Nothing remaining in most cases, but found one complete head in flower bed adjacent to pond. Other remains may have been subsequently cleaned up by fox. Have now covered pond with heavy wire mesh panels, which has prevented any further losses. Setup an IR trail/hunting camera at the weekend, which has captured very clear photos of a large dog Otter as suspected. He has visited most nights around 1am. Currently in process of constructing new ornamental pond, and will definitely be including an electric fence to hopefully avoid having to use ugly mesh covers.

  10. Also live in Frampton Cotterell,South Glos. 100 mts from river Frome. Had koi pond raided by Otter caught on cctv over the last week 8 large fish taken.Looks as if we have well feed otter in the village.

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