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Your Top Pond Questions Answered

By: Dr Gareth Evans - Updated: 4 Mar 2020 | comments*Discuss
Fish Snails Lily Frogswpawn Frogs Water

We love all the comments you pond lovers add to our articles. Many of the comments address the same kinds of issue (but do keep sending them in!) - so we've taken four comments which we feel reflect what a lot of people are asking and our expert has answered them below. We hope you find this useful.

Snails Dying

Hi there, I wonder if you can help me? Over the past week or so all the snails in one of my ponds have died. They have all changed colour from black to light brown. Other pond life appears unaffected. Any suggestions what the problem is? 02/06/12

That certainly is a strange one. The two things which instantly spring to mind are some kind of poisoning, or maybe an infectious illness that clearly only affects snails. Since you say that the deaths have happened in one of your ponds (and so I’m assuming that if there are any snails in the others, they have been left unaffected), poisoning begins to look the most likely.

If you can safely rule out the possibility that any slug & snail-specific pesticides or biological controls could have been washed or wafted into the pond – and there’s no chance that anyone has been a little too enthusiastic with the slug pellets – then my bet would be on the copper level in your water having risen. Just like the copper rings to control their garden cousins, aquatic snails are particularly sensitive to this metal – so it’s probably worth testing your water to see. It will probably mean a water change, then trying to track down the source and work out why it’s only affecting that one pond, but once you’ve done that, everything should be back to normal.

If the copper angle proves inconclusive, however, snails are prone to their own particular set of diseases and parasites, so keep a careful eye on your other ponds for any signs of ill-health and be prepared to isolate any affected molluscs swiftly, to control the spread.

Frog spawn disappearing

Like others, our frog spawn has completely disappeared for the last 2 years. After last year’s experience, we covered the pond with netting so no predators from out of the pond could get at the frog spawn. We has 15-20 large 'lumps' of spawn but again it has completely gone. We have carefully checked the pool and there are no tadpoles. The pond is 10'x4' and up to 3' deep. We have no fish but do have some newts but do not think they could have eaten so much so quickly. Before the last 2 years, the pond would have hundreds of tadpoles in from which we would see quite a few froglets. but none for 2 years. 11/04/12

Unfortunately, as you are obviously aware, what you are describing is becoming an increasingly common – and very depressing – tale. Covering the pond after spawning should certainly have prevented the usual suspects from getting at it, and likewise, I think it’s safe to say the newts are in the clear, which means something else has to be going on.

Water quality has been implicated in a number of instances of ‘vanishing spawn’, since factors such as the pH balance, nitrate and oxygenation may adversely affect the viability – and in some cases, the integrity – of the spawn itself. Since you say that you don’t have any fish in your pond, you may not do the number of regular water quality checks that fish-keepers tend to have to, so it might be worth buying a simple test kit from your local supplier and seeing if that throws any light on things. It’s also probably worth getting in contact with your local wildlife trust, to see if they know of any problems with frog health in the area. As you probably know, chytrid fungus is having serious impact on amphibian populations, so if your frogs are ill, or the population is otherwise in decline, it could simply be that the viability of their eggs is dropping.

There’s nothing else to do this year, but assuming your frogs return next spring, perhaps you might consider collecting some of the spawn and putting it into a tank indoors. If you keep a close eye on it under controlled conditions, you might just find out what’s really happening.

Fish dying suddenly after years of pond keeping

We have had our garden ponds for over 20 years but today our fish have started to die. Even when they are dead they look healthy, bright eyes good colour etc and. no visible signs of disease. Have you any advice please? 02/06/12

How very sad for you; I’m sorry to hear about your problem. After looking after your fish successfully for so many years, I’m sure you’ve already thought of, investigated and ruled out all the obvious things that might possibly have caused it – water quality issue such as nitrate levels and acidity/alkalinity, de-oxygenation as the water has begun to warm up, and so on. If your routine water tests aren’t showing anything out of the ordinary, then it’s probably time to start thinking about some of the more unusual possible causes.

I’m not quite clear whether they have been dying en mass, or more gradually in ones and twos, but given the absence of any signs of damage or disease that you describe – and assuming they haven’t simply succumbed to old age – it’s beginning to sound as if some sudden change has occurred within your pond. If that suspicion is true, then there are two things which immediately come to mind, namely poisoning or electrocution. Have you, or any of your neighbours been spraying pesticides recently, or using any chemicals on your gardens? If so, is there any chance that it might have drifted, or been washed into the water? A lot depends on the volume of your pond, but that might be a possibility to explore, particularly if other forms of aquatic life start to show any ill effects.

It might also be worth having a qualified electrician check over your pump and any other electrical equipment too. No matter how well you maintain them, the years can still take their toll and very occasionally this means that they will cause problems, so it’s definitely a case of better safe than sorry!

Can't grow water lilies

I have a pond with a variety of fish - but I have never been able to keep water lilies. I have been told that the fish eat them - is this true and is there a variety that the fish don't like? 27/05/12

It depends on the particular mix of species of fish you keep, but the simple answer is yes, I’m afraid that it is true. Many kinds will happily eat water lilies – and most other types of pond plants too – when the fancy takes them. Probably the worst offenders tend to be Koi, which are notorious for grubbing up artistic planting arrangements and then munching away on them, but most members of the carp-family (and that includes goldfish, shubunkins, comets and many other common varieties of popular ornamental fish) will have a go from time to time. Exactly how much damage they do tends to vary quite a lot, from a few mildly damaged leaf edges, to out and out destruction – and from your question it sounds as if your fish definitely fit into the committed lily-eater category!

Unfortunately, there doesn’t seem to be much general agreement amongst pond owners on any one particular type of water lily that’s especially unpalatable to fish, but if you really do want to be able to enjoy these lovely aquatic plants in your own garden, there are a few things you could try. One option, if it’s practical for your pond, would be to fence off a section of deep water with suitably sized plastic mesh, to make a fish-proof underwater fence, and grow your lily behind its protection.

Alternatively, you might like to consider giving up on the idea of their peaceful co-existence altogether, and simply construct another pond just for the plants. It needn’t be a big undertaking; there are dwarf lilies such as the tiny flowered Nymphaea pygmaea “Alba” or the variety “Aurora” which will do very well in a tub or barrel – so the good news is, you don’t have to miss out!

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I have just built a raised pond which is about a foot above the ground.I would love to have frogs and toads in the pond eventually and looking to add some large rocks and boulders around the edge which will be OK for when the frogs are in the pond, but my question is will they be able to get into the pond in the first place, being a foot off the ground?
Shazzy - 4-Mar-20 @ 6:31 PM
I lost all my frog spawn and damselfly larvae and found an infestation with water beeltes, Notonata spp. I caught 13 and now see a lot of tiny young in the water. Any control for Notonata? This isgarden pond with no fish.
Kath - 28-Apr-19 @ 3:25 PM
have a small liner pond about 5ft by 3ft and as my fish have all been given away I want to clean it out. Old pump packed up and left it a while but now have new pump as pond smells but I have found loads of baby newts varying in size from half inch to two inch in size and do not want to harm them. how long do I wait for them to grow and can I tip them onto my lawn or do I need to put them in a water filled tub? Many thanks for useful advic
cathy - 18-Aug-18 @ 5:45 PM
I have a moulded pond liner about 5ft by 3ft and want to empty it and give it a good clean as have given away my fish and the water smells when disturbed. I have a new pump to install as other packed up but when I started to net out the debris I discovered loads of baby newts so do not want to harm them. They are varying in size from half inch to three inches. When would it be safe to empty pond and should I put the newts in a tub while cleaning. Planned to pump water out onto lawn and empty bottom sludge onto lawn as well. Will the newts be ok out of water? Sorry-loads of queries! Many thanks for any helpful feedback
cathy - 18-Aug-18 @ 5:33 PM
I am helping a friend that just bought a home that came with a 20’ x 10’ fish pond that is approximately 3.5’ to 4’ at the deepest point and estimated to be 5000 gallons in size.The pond has 2 small waterfalls that are fed by a Pentair Intelliflo pool pump.The filtration system is a Sta-Rite Cristal Flo sand filter. There is a Pentair Lifegard UV Sterilizing system, Model QL-120.I have been told these came from a pool that upgraded their pump/filter system. The problem we are having is fish in the pond have died after using Algaefix and Pondzyme for algae and sludge control.I use the same products on my smaller pond and have no troubles.I think the 2 small waterfalls may not be adequately oxygenating the pond while the Algaefix is killing the algae. I am going to test the water for ph, nitrate, and ammonia levels as soon as the test kit I ordered arrives.If those levels are normal, I am going to suggest the owner buy an aerator pump to enrich the oxygen level of the pond.Would you have any recommendations as to what brand & model would be good for this pond? I also question if a biofilter of some sort is needed to stabilize the pond eco system.If that is a good idea what make & model filter can we adapt to the existing pump/filter system he is using?I am not sure if the swimming pool filter & pump he is using has any contaminants from pool chemicals that may be contributing to the fish deaths. Any suggestions would be gratefully accepted.Thanks…. Rick Lambos
Rick - 29-Jun-18 @ 7:37 PM
HELP! I have just moved and there is a really ugly pond. Purpose built, above ground not a lovely wildlife one. It is being removed and I need to get rid of the frogspawn. Previous owner took fish!! Any advice on how to get rid of it, please
lallyann - 28-Mar-18 @ 9:50 AM
I’m building a pond but not sure which rocks to add that are good for fish and water plants, I have looked in every store and every website but NO ONE could help me out. Could someone PLEASE give me a recommendation!!!
Pond guy - 12-Feb-18 @ 7:35 AM
About 4 months ago I cleaned out my fishpond (relatively small about 2 metres diameter and 30cms deep) and repotted my water lilles removing and dead leaves etc. The lillies now seem to be diseased. There are better black areas appearing along the long side of the leaves which gradually spreads over the whole leaf. When I repotted them (in perforated plastic troughs lined with muslin) I used "top soil" purchased from a garden centre which was also noted to contain some sand and pumice. Could this be the cause of the problem? Any advice you could offer would be appreciated. Regards Bill Smith (New Zealand)
Bill - 10-Jan-18 @ 3:47 AM
I have an almost 20 yr old raised goldfish pond. A tree fell on my house during the recent hurricane and big limbs landed in the fishpond. I guess they stuck holes in my liner as it won't stay filled. Also some of the wood was damaged.I still have a dozen fish. I have to drain and get a new liner and basically start over if I'm going to keep it. I was thinking of using instead a 110 gallon galvanized steel horse trough as my pond. Is it safe to use since it's metal? And would the water get too hot in the summer to be safe? I would appreciate any advice.
Becky - 6-Oct-17 @ 12:18 AM
Why do i have continual white froth on top of my small patio pond. I have now only got 3 very old goldfish left in it The filters are clean and the fish look Ok and feed OK Any suggestions please
Davo - 23-Sep-17 @ 2:55 PM
We have just cleaned out, relined and filled a garden pond which was filthy and leaking (we moved into this house a year ago.) We have a pump and a cascade, oxygenating and other plants, and we allowed the pond to settle for 10 days before returning all the fish, newts and invertebrates (painstakingly saved!).The fish are, we think, roach.Two medium sized and a shoal of fry.We are worried that they are not eating.....we have tried pond flakes, pond sticks and now bloodworm pellets on the advice of a fishing shop.Does anybody have any advice about this, please? - we don't want to lose the fish.
Puzzled - 20-Sep-17 @ 10:50 AM
i am building a raised pond measuring approx 3m X 2m, want to know if a wall thickness of 200mm will be adequate strength? it is all set on a footing base of 300mm deep and 300mm wide, it will be 900mm high.
mark - 25-Jul-17 @ 11:14 AM
Hi, my daughter has a very small pond which attracted at least one large frog and a newt.She has some pond weed in it and bought a water orchid (water lettuce?) to put in the pond.It floated beautifully for a few weeks, then suddenly disappeared overnight!Where could it have gone?Is it a delicacy for some sort of wildlife?(We do have chickens which are allowed to run free and we also have foxes which visit the garden).We are at a loss to know what happened to it.Any suggestions please?
Zande - 18-Jun-15 @ 10:49 PM
We have moved to a new house and we have a problem with Herons so no longer have fish. The pond seems quite healthy and we have a lot of tadpoles, however recently I have noticed what looks like worm casts all aroud the inside of the liner. Any idea of what they aredon't seem to be able to find anything on this. Also are they harmful ?
Sharp - 3-Jun-15 @ 5:17 PM
We have recently moved into a house with a large Pond full of various fish, Koi, Goldfish and others (not sure what they are). We've been feeding them regularly just using flaked food (twice a day 2 handfuls for c. 15 fish). Local pet fish expert suggested getting stick food for Koi, so got a multi type suitable for other fish also. Have fed them 3 times with this so far. Yesterday morning one of the fish was on the pond floor on it's side and it appeared dead. When I bought it to the surface it tried to swim, but seemed to be listing to one side. When I went out this morning, it was dead and another fish (much larger type), was the same, bottom of the pond, listing and lifeless. The only change I can think of is the food. We have a waterfall and a fountain running 24/7 and a UV light on the pumping system. I discovered a frog yesterday (it discovered me by jumping on my foot), but I don;t know if this has always been here. I've read up a bit on the pond/fish and I *think* we're doing the right things, but I don't know why the fish have died. Does anyone have any suggestions or advice please? Roy.
Wildr - 28-Sep-14 @ 12:30 PM
@The hat? Could it be that they have already left the pond and are simply now living under rocks somewhere nearby? Or do you have any new potential predators in your garden?
PondExpert - 23-Jul-14 @ 11:20 AM
My newts have suddenly vanished from my pond. They haven't diedbecause I would have recovered their body's . I've had newts for 14 yrs and last saw them mating this June. This is a mystery, can you help.
The hat - 22-Jul-14 @ 8:22 PM
I have had newts in my pond for a number of years now but over the last 2 days Ikeep finding dead ones any advice on whats wrong
ako - 16-Jul-14 @ 7:18 PM
about a year ago my fish started coming to the top in December and i thought they were hungry. But as we all know fish dont feed below 10 degrees. i took a sample to my local fish supplier and he said water was perfect. he said bring one in. All my fish where about 2 foot long. and all grade AA kio. when i took 1 in he took a swab and said a frog or a bird has been in the pond and infected the fish. I used the rite chemicals but after 2 weeks all but 1 which was a roach my brother caught years ago on the canel. so after nearly 30 years doing my pond i lost them all to a frog or bird. BEWARE everyone.
mick - 21-Jun-14 @ 2:00 PM
Thanks for the great tips Pete. Love to hear from anyone else with great suggestions too.
PondExpert - 10-Jun-14 @ 12:25 PM
REF.WATER LILIES IN A CARP POND. I had the problem with fish uprooting and eating the lilies.The solution I found was to use three round water lilie baskets . STEP1.Wire two baskets base to base. STEP2.Plant the lilie in the top basket. STEP3.Cut the bottom out of the remaining basket, place it upside down over the basket containing the lilie, wire the two together so that the upturned basket acts as a fence to protect the lilie.I hope this is helpfull as it works for me,good luck Pete.
Pete - 9-Jun-14 @ 2:42 PM
DORIS - 24-May-14 @ 5:52 PM
My pond seems green and all the frogs spawn which also seems to have a green film around and water snails are dead. I have found pine needles and pine cones in there from a nearby pine tree could this be causing the problem
Lyn - 4-Apr-14 @ 4:03 PM
I have a small pond it was actually our old bath. we sank it to be a bog garden but its full of frogs . It is full of plants and should not be suitable for them at all. I would like to grow a water cleaning reed , but can't find one small enough. Any suggestions please
Patty - 15-May-13 @ 9:38 PM
We have recently moved and inherited a fairly large pond which looks as if it hasn't been touched in years. We are going to clean it as the weather gets warmer, but there seems to be a huge number of fish in there. Should I sell the excess? Are they worth anything, or do I give them away?
Harry - 14-Apr-13 @ 3:10 PM
three years ago i made a fish pond for my children, using a whiskey keg bought from the garden centre, four fish have lived happily in it. but after the last bout of really heavy snow, three have died. children devastated and so i was going to go out and buy some more tomorrow now bad weather passed, friend says i cant do that, says they will get eaten by present fish, says fish have to be bought all at the same time??? is this true
sue - 10-Apr-13 @ 10:32 PM
just had a pond done,filled 1 week ago-and added 4 small gold fish sunday now all dead tuesday (bad weather last 2 days wind rain ect) did not test water for chlorine ect-should I leave for 3-4 weeks now STU y
stu - 25-Sep-12 @ 6:07 PM
I have a pond measuring appx 15m X 15m. This september and last september one of the water lilies has grown hugely from the centre with leaves up to 70cm high and spreading to the whole plant, with the flowers dying off to the edges. What might be wrong. ?.
neptune - 16-Sep-12 @ 8:55 AM
my pond has been crystil clear for two years now,i have a eco power uv filter.pumping at full capicity. just in the last few weeks my pond has gone realy mirky brown green ans has a bad smell, i have changed the uv tube and did a part water change but a few days later its the same. When i clean the filter its almost cloged up with sludge,,my fish seem happy enouge,whats wrong ,some idias please please.
hosta - 8-Jul-12 @ 12:30 PM
I am having a problem with oxygenating weed in my small pond. It is like a sargasso sea! Soon, I think the newts will be wandering across the top. I can't thin it out yet because it has been a great year for newts and we have tons of babies. They are at the " fish" stage so we can't take them out and put them back. Any ideas on when it will be possible monthwise to sort it? We don't want to do any damage. Thanks Carol
Carol - 8-Jul-12 @ 10:52 AM
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