Over-cleaned pond? - fish slow and not eating

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Hi all, after some advice!

Quick pond history

- Inherited pond with house 10 years ago, didn't know what I was doing, low maintenance, lots of fish died about 4/5 years ago
- 3 years ago replaced pump, all filter sponges, filter ballast, UV bulb, clean out
- Every year, overrun with string algae, huge amount of sludge, fish barely visible

Last week

- Emptied pond (thorough clean (maybe too much, got rid of every sign of algae and muck i could))
- Cleaned filters for first time in 3 years (cleaned in pond water)
- Used a very highly recommended string algae control in the UK (turns water cloudy for a few days)
This took about 12 hours start to finish

Concerns

- Fish seem slightly less active - I have however put some new plants in and a water lilly, some are hanging out under the lilly quite a bit - they used to all stay under the waterfall but this has been so well cleaned, maybe not enough cover for them all anymore as all muck and algae gone
- My fish have never eaten!!!
- - What I mean by this is, in 10 years of throwing in fish food, not once have they come to the surface to eat. The food floats around for a few days and disappears over the course of a week or so - don't know if they are eating it, or it is dissolving and just falling to the bottom?
- The cloudiness has largely gone, but there is a pale coating on exposed parts of rocks, pump, pipes, underwater plants, margin plants on parts that meets water

Have I cleaned the pond too well, maybe taken away their main source of food (algae etc...), and now they have lost that food source, they are also not eating the pellets, so are slowing down due to lack of food?

They are usually pretty scaredy when anyone goes near the pond, but the ones hovering under the lilly (which is otherwise out in the open), do not budge!
Is this because they feel safe under the lilly, or are too hungry to move?

Any advice on what the issue could be (if indeed there is one), and any possible remedy would be appreciated.

15'ish x mid size goldfish (4" - 6"), 15'ish x small/baby goldfish (1" - 2") - I think they are all goldfish
Water strip test - all good, KH may be a little high, but I don't think water hardness would cause these issues
Laguna 5000 Pump
Filtoclear 11000 filter
Kidney shape fibreglass pond - approx. 3500 ltr
 
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You are correct in thinking you cleaned it too well. It's generally not suggested to empty and scrub out a fish pond unless there is a serious chemical intrusion or something detrimental like that. By doing that you got rid of all the good bacteria. Now it will take some time for your pond's ecology to recover. New beneficial bacteria will take a few weeks to repopulate. The bio film that covers your liner will also take a while to reform.

The only things you should be doing is rinsing filter pads, if applicable backwashing the filter and if need be scooping out bottom muck with a net or a pond vac after several months of accumulation.

It can also be stressful on the fish when you do a large water change. So many things can affect them such as different and sudden water temperature change, Ph, minerals, etc.

I hope you have plants in your pond. They are an essential part of the ecology that help with filtration. Just like they clean our air, they help clean the water.

Just be patient and it should all work out.
 

mrsclem

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All good advice from poconojoe. Let me add one thing, whatever fish food that doesn't get eaten in 5 minutes should be scooped out. It will only add the the poor water quality.
 
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Thanks for the advice both.

Plants have always died off very quickly, so haven't had any since this last clean, where I added a few bottom oxygenators, a water lilly, half a dozen bunches of weighted oxygenators and half a dozen marginals.

I will hold tight and see how things develop over the next week.

I am, however, still confused about the feeding. The fish have never come up for food since the day we got the house - could they have been feeding on algae and whatever else is in the water all this time, or are they more likely waiting for the pellets to sink?
 
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I don't know why everyone hates string algea so much! It had a job: sick up excess nutrients. The waste built up over winter, and untill bigger plants wake up and use it, the string algea gets it out of the water colum. I understand disliking the single cell free floating kind, it turns water into pea soup so we can't see anything.
For future springs, let the algae be untill your plants kick in, then use a pond only dedicated toilet brush to twist it up and remove it. Meanwhile, next time you can try feeding the fish the ends off of cucumbers, some watermelon, with rind on, just make sure they are clean before you dice them up. Id toss the watermelon in and let the fish work it over untill it was nothing but rind, my fish loved it. They may not see flakes or pellets as food, and it sounds like they don't see humans as care givers, so try just sitting at the edge of the pond while you drink a cup of tea or coffee and ignore them while you read up. Do that whenever you have time and the weather is nice. Eventually, when they ignore you and resume normal activity, you can try introducing a bit of food.
 
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Thanks JamieB, will try that (the string algae had completely overrun the pond - you could not see through it for the entire width of the pond)

IMG_1236.JPG

@Mmathis - Kidney shaped - very approximate. longest 3m, widest 1.5m, depth 0.8m - around 3,500 litres

White fibreglass - I get that the fish welfare is all important, but it is such an eyesore and does not look at all natural with that dirty white reflective surface (we did consider filling it in a couple of years ago when it was becoming such a task).

However, I am doing a lot of work in the garden right now and tidying up and replanting the whole area so am spending what is required to get the pond looking good - would like to either paint the pond black, or fit a black liner at some point so we can enjoy it more.
Recommendations for either of those appreciated also?

IMG_1282.JPG

And yes - I do see the difference between the two pictures shows how much I really did overdo the cleaning :(
 
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That's an interesting pond material. I've never seen anything like that. It definitely looks real sturdy. I wonder if it was meant to be a swimming pool?

I guess you could lay a flexible black liner in there if you really wanted to. Seems like a lot of work to do that though. You'd have to empty it all out to do that and any fish would need to be temporarily housed in an appropriate container. A plastic kiddie pool works good for that. Then there's the concern that water may get between the existing base and the new liner. And laying the liner throughout all those curves might be troublesome.

I, personally would leave it, but that's up to you.

Some people lay river pebbles or even large stones in their ponds to hide the liner, but I don't know what you would do for the walls.

They do make a brush on liquid liner, but I don't know how well it would stick to that material. You would have to maybe clean it good and rough it up with sandpaper.
 

IPA

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Welcome. It isn’t the worst looking liner and once you get a coat of algae it will be more green and brown. Put in plant baskets and some rocks. They make a paint for concrete and fiberglass liners that is safe for ponds; I searched for it here but couldn’t find any posts. Seems paint is a popular subject.
Agree it would be a lot of work and expense. You’d need to purchase another large liner, freed trough or tub for the fish while you cleaned, dried, painted, and dried again the old liner. If you were to use EPDM liner it isn’t all that flexible. Maybe a new build and going larger so that could be a long term plan and live with what you have for now. PVC liner doesn’t hold up well by itself but if you were just lining the existing liner it’s a lot more flexible and cheaper, though a lot of pond stores won’t even sell it. It’s what the big box and home improvement stores carry and over priced from them IMO.
 
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Thanks all!

I think it is a molded plastic/sanded fibreglass liner - I am guessing it is at least 25-30 years old based on the time the previous owners lived here and when the garden was landscaped.

Was considering paint, but there doesn't seem to be one on the market I can find (or on this forum), that doesn't get a degree of poor reviews due to not lasting and cracking.

I definitely won't be replacing the existing liner, so was thinking my best bet would be a PVC liner direct on top of this one.
Housing the fish wouldn't be an issue, just unsure about the appearance of any folds around the edge that there would inevitably be (although I am not overly bothered about this), and would these folds become a bit of a storage/breeding ground for any unwanted muck and algae that would be difficult to access to clean?

I could fold the liner over the surrounding brickwork and somehow secure underneath for the majority of the perimeter, just not sure how I would make the liner watertight under the waterfall section where there really isn't anywhere to tuck it under?

Liners 5m x 3.5m come in at between £80 - £120
 
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Member IPA has a point. Once the pond matures, there will be a nice green coating all over everything and the fiberglass may not be as noticeable. If it were me, I'd just leave it. That's a really nice molded pond.
Many people have ponds that are more contemporary made of materials other than rubber, such as concrete, blocks, bricks, tile, even old swimming pools. I go to a Chinese restaurant that has an indoor pond and it's concrete with tile. It's nice.
 

sissy

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YIKES over cleaned is not the words I would use but you could say way over aggressive cleaning .And chemicals were no help .Sad to say but companies make them sound like a miracle worker and it is all for money .Sorry you had to go through all this ,but i guess at 1 time or the other we make mistakes but learn from them ,
 
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My vote is to stick with the pond as is. It'll develop a green carpet moss on it and the white will be far less noticeable. In the future, when you clean, leave the carpet moss on the sides and bottom.

I agree with placing plant baskets in the pond, it'll be good for water quality, look nice and cover some of the bottom.
 
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That is a LOT of string algae... but with few other plants in the pond nature will definitely lend a helping hand. Potted plants are great, but if you can get them growing directly in the pond that's even better. I think marginals do the most for removing nutrients from the pond. Lilies are lovely, but are really more important for providing some shade and hiding places for your fish. They don't do much for helping clear the water.

You have a nice wide shelf in your pond. I would get some rocks and gravel and create some plant pockets and get plants growing right in the pond. Don't worry too much about muck and algae - a healthy pond has a good amount of both. Remember - it's a pond, not a swimming pool!
 

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