Hello,

i am new to the forum, and also new to keeping fish. My husband and i bought a house which has a pond with fish in it. Neither of us have ever kept fish before and are learning as we go.

The pond is about 330 gallons with 47 (yes 47) fish in it, which i get the impression is a bit too many. 2 are koi and the other or goldfish.

Over winter we kept the waterfall going to stop the pond form completely freeing over and didn't feed them until it started warming up. This appears to have worked as we didn't lose any fish. I also bough some water testing strips that test for PH, total hardness (GH/TH) Nitrite and Nitrates. They have all been within the normal range.

We have been taking advice from a local pond centre and on their advice cleaned the pond using an aquavac. we completely cleaned out the pond which has about 3 inches of sludge at the bottom of it. We refilled it with tap water and put loads of de-clorinator in it, as well as some stuff recommended by the shop to help kick start the good bacteria in the pond.

Since the clean (3 days ago) the fish have started flashing. again the shop asked us to bring in some water to test and the ammonia levels were high so we have treated the water with something to combat this. We are told this will take a few days to sort out the problem with the ammonia.

I have a few questions:

1) One of the fish has slightly red gills today, is this something to do with the high ammonia levels, and will this be sorted once the levels return to normal?

2) two of the fish who were gold have started losing their gold pigment and are turning white. Is this normal? some of the other fish are already like this and have a silvery/goldie with a few black bits type appearance.

3) Some of the black fish are turning gold which i believe is normal, but 1 or two of the black fish are also losing black pigment and going white.

4) am i being too hypochondriac about my fish!

5) any other tips for keeping pond fish?

Thank you to anyone who can help.

Lozsenge

Chillinator to the rescue...

There is something I particularly dislike about people who sell homes with ponds full of fish, in the ideal world the fish should be removed, passed on to other homes and the pond filled in.

Certainly 47 fish is too many for a 330 gallon pond, if there was another zero after this figure you'd be fine, but 330 gallons is too small; particularly for the Koi which can grow to 90cm/3ft in length and need a large, deep pond with a good filtration system. Does the pond have a filter?

To test your water, don't use test strips as these are notoriously unreliable. Instead, buy a good quality liquid test kit.

Without wanting to sound rude, the only useful item that your local pond retailer has sold you is the aquavac. Bottled bacteria supplements are next to useless (how can bacteria survive in a sealed bottle for weeks on end?), ammonia-removing chemicals and resins don't work (they only 'mask' the ammonia or convert it into the equally lethal Ammonium, NH4, which is undetectable on ordinary liquid test kits).

The 'flashing' and red, inflamed gills shown by the fish are indeed symptoms of the ammonia. Specifically, it's ammonia poisoning. Ammonia is lethal (it severely reduces dissolved oxygen uptake and damages gill tissue) in concentrations above 0ppm (parts per million, also called mg/l.) and the toxicity of ammonia increases with the pH and temperature of the water.

As I pointed out above, the chemicals you've been sold won't cure the problem, you need to get down to the root cause and work from there. As it is, the pond is grossly overstocked. This is made even worse if the pond doesn't have a filter to break down solid (in other words, faeces) and chemical (e.g. ammonia, nitrite) waste; and I'm assuming it doesn't.

What you need to do right now is buy a test kit, carry out several large water changes (≥50%), ditch the store giving you the advice and selling you stuff and either start re-homing about 95% of the fish or start digging a very big pond (4 x 4 x 1.8m as a mininum for what you've already got). Also cut out any feeding, as decomposing food will increase the ammonia levels since it appears the pond has no filter to remove it.

The fish might look happy at the moment, but the fact is they're simply taking a long time to die. Fish don't always show external signs that something is wrong.

We do have a filter, we have a Fishmate 15000 with uv.

Thanks for the advice, We don't have the ability to either make the pond bigger or build a bigger one so we will try and re-house a lot of the fish, buy a liquid testing kit and also change the water and see how we go.

We feel very guilty that the fish aren't living in a better environment and are just trying to make it as good as we can.

We sort of expected the pond to have been empty when we bought the house, but apparently it had been rented and therefore the tenants didn't own the fish or have anywhere to take them too.

Any ideas about the pigment changes? I've looked online and i don't thinks its a disease as such as there are no raised bumpy bits or spots, but hey what do i know!

Lozsenge

That sounds about right, whoever built the pond has bought a filter that is rated for ponds 10 times the volume of this one. It's a common trick among fishkeepers to buy over-sized filters in the belief they can add more and more fish; even though they know the risks of the filter blocking and the extra demands placed on dissolved oxygen in the pond water.

Goldfish fry are nearly always brown-black, after a few months to maybe just over a year the gold coloration for which they're famed for (caused by the pigments known as carotenids and pteridines which are acquired from chemicals in their food; fish - like other animals - can't synthesize these pigments naturally), however some (including wild goldfish) develop a silver-grey sheen and some never lose their brown-black coloration; or at least not all of it. Many factors including genetics, diet and water quality all have an effect.

We've just been into the local pet shop to buy a liquid testing kit but they had run out! However they did do an ammonia check for us and it was absolutely fine. (i didn't get the actual reading but it was the lowest colour so i am assuming that was nil).

They lady in the pet shop (a different one to the original shop i spoke about) said that she thinks we cleaned the pond too much and did everything too quickly which may have stressed the fish. She said the symptoms sounds like white spot, and on returning and looking a lot more closely, there may be a few white spots on the fish.

We have now treated with Medifin which is a mixture of formaldehyde and Malachite green so hopefully that will clear it all up.

Once the fish are better i have found a fried who is willing to take about 10 fish and i will endeavour to re-house some more.

Thanks for your help.

Lozsenge

With ammonia levels above 0ppm, heavy maintenance would certainly have done less damage to the fish than the ammonia. Water changes need to be carried out right away to bring it under control. Removing all the sediment from the bottom of the pond would also have removed a lot of decaying organic material which would have been producing more ammonia as it was decomposing.