Natural pond and fish health
Discussion
Hi
We have a large pond that we built around 12 months ago and are trying to let it be a natural pond. It is about 13m x 13m and about 1m deep at the deepest. The water is all rainwater or from our own natural spring.
We have a number of plants in it including oxygenators and lilies etc which all seem to be doing well. If we sit quietly by the pond we see lots of different insects on and under the water, we have frogs, toads and even newts, all of which seem to be thriving. We also have 3 solar fountains that bubble along gently.
We left the pond like this for almost a year for that stuff to establish.
About 5 weeks ago we introduced some goldfish, 9 gold and 9 mottled looking. Since then we have had 3 dead fish, all mottled. The last one looked as though it had been bitten in a couple of places, once near its tail.
We started feeding them everyday when they arrived but then stopped this moving to every three days or so. Our thinking being that there is a lot of natural stuff for them to eat and anything we added was simply supplementary.
As everything else seems to be doing well it doesn’t feel to me like a water quality or oxygen issue, but I could be wrong.
We have no idea why they died and was wondering if anybody had any thoughts and if there is something else we could be doing to help the others survive and thrive?
We have a large pond that we built around 12 months ago and are trying to let it be a natural pond. It is about 13m x 13m and about 1m deep at the deepest. The water is all rainwater or from our own natural spring.
We have a number of plants in it including oxygenators and lilies etc which all seem to be doing well. If we sit quietly by the pond we see lots of different insects on and under the water, we have frogs, toads and even newts, all of which seem to be thriving. We also have 3 solar fountains that bubble along gently.
We left the pond like this for almost a year for that stuff to establish.
About 5 weeks ago we introduced some goldfish, 9 gold and 9 mottled looking. Since then we have had 3 dead fish, all mottled. The last one looked as though it had been bitten in a couple of places, once near its tail.
We started feeding them everyday when they arrived but then stopped this moving to every three days or so. Our thinking being that there is a lot of natural stuff for them to eat and anything we added was simply supplementary.
As everything else seems to be doing well it doesn’t feel to me like a water quality or oxygen issue, but I could be wrong.
We have no idea why they died and was wondering if anybody had any thoughts and if there is something else we could be doing to help the others survive and thrive?
The first thing to say is that I’m afraid you shouldn’t have put goldfish in there if you are aiming for a ‘natural pond’ - goldfish will soon clear the wildlife, breed like buggery and make the pond filthy!
I’d remove them. If the dead ones were long finned types, then the others probably had a go at them. Also - any Herons or Kingfishers around?
I’d remove them. If the dead ones were long finned types, then the others probably had a go at them. Also - any Herons or Kingfishers around?
Yes, it takes quite a few years for a natural pond to establish itself with regards to the water chemistry. You've introduced fish which pee and poo and that's highly toxic ammonia to them. The only way to counter this is to either wait a for more years before adding fish or adding a filter system. There's specific bacteria which grows that neutralises the ammonia which turns it into nitrite and then other bacteria turns nitrite into nitrate. There are chemicals on the market like ammonia and nitrite lock but this becomes quite expensive. You can grab a decent water testing kit off Amazon and check your water parameters with that.
I started with an ornamental pond, which once I got bored became 'natural'. Saved a lot of electricity and once the frogs, toads and newts moved in, so did a load of other stuff. After that I had to buy a few sticklebacks (what happened to kids who would go and catch some?).
Anyhow, the sticklebacks are part predator and part prey. Overall is all equalled out. I suspect that goldfish are just too hungry to sit well with the other native species. A natural pond will not last long with a high toxic load or predatory species. My pond was a uniform 75cm and around 10 x8m, so yours should be large enough to reach an equilibrium point. It is probably down to careful species selection.
I ended up fitting a pond camera, wired back to the kitchen telly - absolutely fascinating!
Anyhow, the sticklebacks are part predator and part prey. Overall is all equalled out. I suspect that goldfish are just too hungry to sit well with the other native species. A natural pond will not last long with a high toxic load or predatory species. My pond was a uniform 75cm and around 10 x8m, so yours should be large enough to reach an equilibrium point. It is probably down to careful species selection.
I ended up fitting a pond camera, wired back to the kitchen telly - absolutely fascinating!
We have a pond approx 40m x 12m, through and through from a small manmade stream.
We left it to go natural - that was a mistake, some grassy weed completely took over and was a bugger to clear.
It used to have loads of fish - roach I think, but they've all gone now. (Otters / heron / cormorant controlled the population but then they just disappeared)
Now it has been completely taken over with some sort of pond weed. I think that part of the problem is that the adjacent water meadows, used for grazing calves for part of the year, flooded more than usual and I think we got the super high nutrient run off.
Any ideas on sorting out the pond weed - it appears to be attached at the bottom and then forms rafts on the surface, grows like crazy when the sun shines. The gardeners thought that the water quality couldn't be too bad as there were quite a few fresh water mussels when they removed the grass weed, leeches as well.
There's quite a lot of water there, max depth about 1.8m though most of it less than 1m, but a hell of a lot to treat and it is connected to the waterways... some sort of oxygenation ? pump / fountain?
We left it to go natural - that was a mistake, some grassy weed completely took over and was a bugger to clear.
It used to have loads of fish - roach I think, but they've all gone now. (Otters / heron / cormorant controlled the population but then they just disappeared)
Now it has been completely taken over with some sort of pond weed. I think that part of the problem is that the adjacent water meadows, used for grazing calves for part of the year, flooded more than usual and I think we got the super high nutrient run off.
Any ideas on sorting out the pond weed - it appears to be attached at the bottom and then forms rafts on the surface, grows like crazy when the sun shines. The gardeners thought that the water quality couldn't be too bad as there were quite a few fresh water mussels when they removed the grass weed, leeches as well.
There's quite a lot of water there, max depth about 1.8m though most of it less than 1m, but a hell of a lot to treat and it is connected to the waterways... some sort of oxygenation ? pump / fountain?
jmsgld said:
We have a pond approx 40m x 12m, through and through from a small manmade stream.
We left it to go natural - that was a mistake, some grassy weed completely took over and was a bugger to clear.
It used to have loads of fish - roach I think, but they've all gone now. (Otters / heron / cormorant controlled the population but then they just disappeared)
Now it has been completely taken over with some sort of pond weed. I think that part of the problem is that the adjacent water meadows, used for grazing calves for part of the year, flooded more than usual and I think we got the super high nutrient run off.
Any ideas on sorting out the pond weed - it appears to be attached at the bottom and then forms rafts on the surface, grows like crazy when the sun shines. The gardeners thought that the water quality couldn't be too bad as there were quite a few fresh water mussels when they removed the grass weed, leeches as well.
There's quite a lot of water there, max depth about 1.8m though most of it less than 1m, but a hell of a lot to treat and it is connected to the waterways... some sort of oxygenation ? pump / fountain?
Have you got a pic of the pond weed? We left it to go natural - that was a mistake, some grassy weed completely took over and was a bugger to clear.
It used to have loads of fish - roach I think, but they've all gone now. (Otters / heron / cormorant controlled the population but then they just disappeared)
Now it has been completely taken over with some sort of pond weed. I think that part of the problem is that the adjacent water meadows, used for grazing calves for part of the year, flooded more than usual and I think we got the super high nutrient run off.
Any ideas on sorting out the pond weed - it appears to be attached at the bottom and then forms rafts on the surface, grows like crazy when the sun shines. The gardeners thought that the water quality couldn't be too bad as there were quite a few fresh water mussels when they removed the grass weed, leeches as well.
There's quite a lot of water there, max depth about 1.8m though most of it less than 1m, but a hell of a lot to treat and it is connected to the waterways... some sort of oxygenation ? pump / fountain?
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It’s blanket weed - caused by high nutrient levels in the water and too much sunlight.
With smaller garden type ponds you would ideally have the pond well planted so that the plants use the nutrients in the water and their presence also helps provide shade. You can also use barley straw pads/extract to help treat blanket weed. But this becomes rather difficult on such a large pond, particularly if it’s really just a hole in the ground without good planting with aquatic and semi aquatic marginal plants. Trees can also sometimes help shade the pond, though leaf debris in the water will raise nutrient levels to work against you.
What’s the landscaping and aquascaping like with your pond?
With smaller garden type ponds you would ideally have the pond well planted so that the plants use the nutrients in the water and their presence also helps provide shade. You can also use barley straw pads/extract to help treat blanket weed. But this becomes rather difficult on such a large pond, particularly if it’s really just a hole in the ground without good planting with aquatic and semi aquatic marginal plants. Trees can also sometimes help shade the pond, though leaf debris in the water will raise nutrient levels to work against you.
What’s the landscaping and aquascaping like with your pond?
yellowtang said:
It’s blanket weed - caused by high nutrient levels in the water and too much sunlight.
I'm trying to work out whether it's just pure balnket weed or if there's another plant bound up in it underneath. Hydra international do commercial treatments that work really well.
18 goldfish in 169 square meters won’t be affecting the water chemistry significantly. Wouldn’t like to guess what’s killed a few though. Do the rest look ok?
As for the other pond, with a natural inflow and outflow I would not use any chemical treatments because you’ll affect whatever is downstream. You’re also restricted in your ability to alter the water chemistry. I’d turn a big chunk at the inflow end into a reed bed and physically remove the weed from the other end with a rake.
As for the other pond, with a natural inflow and outflow I would not use any chemical treatments because you’ll affect whatever is downstream. You’re also restricted in your ability to alter the water chemistry. I’d turn a big chunk at the inflow end into a reed bed and physically remove the weed from the other end with a rake.
pocketspring said:
Yes, it takes quite a few years for a natural pond to establish itself with regards to the water chemistry. You've introduced fish which pee and poo and that's highly toxic ammonia to them. The only way to counter this is to either wait a for more years before adding fish or adding a filter system. There's specific bacteria which grows that neutralises the ammonia which turns it into nitrite and then other bacteria turns nitrite into nitrate. There are chemicals on the market like ammonia and nitrite lock but this becomes quite expensive. You can grab a decent water testing kit off Amazon and check your water parameters with that.
Goldfish are highly resistant to ammonia damage. I'm not saying it's okay to have ammonia in the water, but it's unlikely to have killed them unless the levels are sky-high.I think it's more likely they were either diseased before the OP bought them or bred from poor stock.
yellowtang said:
It’s blanket weed - caused by high nutrient levels in the water and too much sunlight.
With smaller garden type ponds you would ideally have the pond well planted so that the plants use the nutrients in the water and their presence also helps provide shade. You can also use barley straw pads/extract to help treat blanket weed. But this becomes rather difficult on such a large pond, particularly if it’s really just a hole in the ground without good planting with aquatic and semi aquatic marginal plants. Trees can also sometimes help shade the pond, though leaf debris in the water will raise nutrient levels to work against you.
What’s the landscaping and aquascaping like with your pond?
It's an old / well established pond. With smaller garden type ponds you would ideally have the pond well planted so that the plants use the nutrients in the water and their presence also helps provide shade. You can also use barley straw pads/extract to help treat blanket weed. But this becomes rather difficult on such a large pond, particularly if it’s really just a hole in the ground without good planting with aquatic and semi aquatic marginal plants. Trees can also sometimes help shade the pond, though leaf debris in the water will raise nutrient levels to work against you.
What’s the landscaping and aquascaping like with your pond?
There is an area of bull rushes - maybe 15% cover,
One side has some significant ornamental aquatic plant - another 10%.
Then there is the grass like plant that went mad last year and was taking up 60% of the pond, we had the vast majority of that manually removed though it's now trying to come back but currently less than 10%. The pond weed started at the same time that these went mad.
There are some water lillies, but minimal cover
I think it is probably from the excessive nutrients from the run off of the water meadows. I think I'll wait until the stream dries up in the summer and so there is not a constant water change, then treat it with the suggested chemicals from Hydra. This ? https://www.hydra-int.com/lake-clear.html
Tahnks
jmsgld said:
It's an old / well established pond.
There is an area of bull rushes - maybe 15% cover,
One side has some significant ornamental aquatic plant - another 10%.
Then there is the grass like plant that went mad last year and was taking up 60% of the pond, we had the vast majority of that manually removed though it's now trying to come back but currently less than 10%. The pond weed started at the same time that these went mad.
There are some water lillies, but minimal cover
I think it is probably from the excessive nutrients from the run off of the water meadows. I think I'll wait until the stream dries up in the summer and so there is not a constant water change, then treat it with the suggested chemicals from Hydra. This ? https://www.hydra-int.com/lake-clear.html
Tahnks
Yep, that's the stuff to use. No need to worry about it floating away, it's granular based. Wait for a calm day and start spreading it over the water. It'll start to sink and do its work. There is an area of bull rushes - maybe 15% cover,
One side has some significant ornamental aquatic plant - another 10%.
Then there is the grass like plant that went mad last year and was taking up 60% of the pond, we had the vast majority of that manually removed though it's now trying to come back but currently less than 10%. The pond weed started at the same time that these went mad.
There are some water lillies, but minimal cover
I think it is probably from the excessive nutrients from the run off of the water meadows. I think I'll wait until the stream dries up in the summer and so there is not a constant water change, then treat it with the suggested chemicals from Hydra. This ? https://www.hydra-int.com/lake-clear.html
Tahnks
yellowtang said:
I’m sure the Hydra product is good, I’ve seen others work well. But ideally you’d address the cause - could you divert the stream and control it via a sluice gate? Can you also increase cover? Ideally around 2/3 of the surface should be shaded.
I think that the problem came from the isolated incident of when the river flooded more than usual and high nutrient water / silt from the water meadows swamped the pond. The stream is diverted from the river Frome and so should be of good quality. otolith said:
18 goldfish in 169 square meters won’t be affecting the water chemistry significantly. Wouldn’t like to guess what’s killed a few though. Do the rest look ok?
As for the other pond, with a natural inflow and outflow I would not use any chemical treatments because you’ll affect whatever is downstream. You’re also restricted in your ability to alter the water chemistry. I’d turn a big chunk at the inflow end into a reed bed and physically remove the weed from the other end with a rake.
No more dead since the last post and the rest look well, they are very active and we can watch them feeding.As for the other pond, with a natural inflow and outflow I would not use any chemical treatments because you’ll affect whatever is downstream. You’re also restricted in your ability to alter the water chemistry. I’d turn a big chunk at the inflow end into a reed bed and physically remove the weed from the other end with a rake.
We have taken to adding a small amount of food every day at the moment to see if that helps, the fish do seem to eat it all.
As an aside the water lilies have broken the surface now which is great to see.
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