backyard pond fish die off

[puckerup]

I have had a 280 gallon pond for about 8 years. Have had almost all of the original fish there for years. They reproduce each year and I keep some of the babies. I have had maybe 6 fish die in these past years. Since end of April beginning of May, after cleaning the pond, have had 2-3 die each week. Checked the levels 3 weeks ago, nitrate was high, put in the Bio stuff, levels great for past 2 weeks. Added some plants. Fish die off has stepped up, now finding 1 or 2 dead each day. At the most have had 20 goldfish at a time, gave some away to neighbor who had heron problem. Down to about 6 now.
Here are some new things;
introduced 2 small Koi 2 weeks ago
added a Lily plant with new aquatic soil. at first soil caused cloudy water, now fine
clean the filter every 4 days now

 

[max384]

There are a lot of people here who know a heck of a lot more than me, but to start, some questions.

What were the other water test results?

What sort of filter system do you have? Pump size?

How deep is your pond? Is it in the sun? What zone are you located in? (or just location)

How big are (were) your fish?

Did you quarantine your new koi before introducing them?

What time of day did your fish die?

A 280 gallon pond is pretty small, and it sounds like you had too many fish. And that size pond is definitely too small for koi. They may be small when you buy them, but they grow fast. Also, when you're experiencing unexplained fish die-offs, that is definitely not the time to add more fish to your pond. I'm not trying to scold you after the fact, just pointing this out so that you don't add more while you're trying to figure out why the fish you have are dying.

 

[sissy]

Could you maybe go to a bigger pond so you could keep that many fish safely (koi get big )and also do you have city water and did you treat it .

 

[Dave 54]

So your pond was fine until you cleaned it eh then the fish started to die off can you give me a description of exactly what is happening ?
I have a feeling that in cleaning up the pond you have inadvertantly started of a bacterial infection and that this is killing your fish.
I do tend agree with both Max and siissy that your pond had alott in the way of fish load , I've a feeling you pushed the envelope too much

Dave

 

[puckerup]

I have had a 280 gallon pond for about 8 years. Have had almost all of the original fish there for years. They reproduce each year and I keep some of the babies. I have had maybe 6 fish die in these past years. Since end of April beginning of May, after cleaning the pond, have had 2-3 die each week. Checked the levels 3 weeks ago, nitrate was high, put in the Bio stuff, levels great for past 2 weeks. Added some plants. Fish die off has stepped up, now finding 1 or 2 dead each day. At the most have had 20 goldfish at a time, gave some away to neighbor who had heron problem. Down to about 6 now.
Here are some new things;
introduced 2 small Koi 2 weeks ago
added a Lily plant with new aquatic soil. at first soil caused cloudy water, now fine
clean the filter every 4 days now

Thank you for your answer. Will collect all the info and get back....

 

[puckerup]

Could you maybe go to a bigger pond so you could keep that many fish safely (koi get big )and also do you have city water and did you treat it .

Cannot go to a bigger pond, yes have city water and have never treated it. It's so mysterious because we have been doing the same thing year after year but now...disaster!

 

[puckerup]

So your pond was fine until you cleaned it eh then the fish started to die off can you give me a description of exactly what is happening ?
I have a feeling that in cleaning up the pond you have inadvertantly started of a bacterial infection and that this is killing your fish.
I do tend agree with both Max and siissy that your pond had alott in the way of fish load , I've a feeling you pushed the envelope too much

Dave

Thank you for your reply.
Mostly find fish dead in the morning, but some have died during the day. As I said, we have kept some of the babies that were born in this pond. They range from 1-5 years old. They were ALL brown. These are the fish which died first. The only brown ones left were born last year. BTW, there was active spawning going on last week.
The fish that have dies looked perfectly fine when I examined them, no marks or discoloration. They seemed a good weight, not skinny. Since we only have 6 fish now, do you think the overcrowding is still a problem?

 

[puckerup]

There are a lot of people here who know a heck of a lot more than me, but to start, some questions.

What were the other water test results?

What sort of filter system do you have? Pump size?

How deep is your pond? Is it in the sun? What zone are you located in? (or just location)

How big are (were) your fish?

Did you quarantine your new koi before introducing them?

What time of day did your fish die?

A 280 gallon pond is pretty small, and it sounds like you had too many fish. And that size pond is definitely too small for koi. They may be small when you buy them, but they grow fast. Also, when you're experiencing unexplained fish die-offs, that is definitely not the time to add more fish to your pond. I'm not trying to scold you after the fact, just pointing this out so that you don't add more while you're trying to figure out why the fish you have are dying.

Thank you for your reply.
Will collect all this info and get back....

 

[Dave 54]

Thank you for your reply.
Mostly find fish dead in the morning, but some have died during the day. As I said, we have kept some of the babies that were born in this pond. They range from 1-5 years old. They were ALL brown. These are the fish which died first. The only brown ones left were born last year. BTW, there was active spawning going on last week.
The fish that have dies looked perfectly fine when I examined them, no marks or discoloration. They seemed a good weight, not skinny. Since we only have 6 fish now, do you think the overcrowding is still a problem?

I would say no its no longer a problem on the other handhowever what your fish are dying from may still finish off any remaining fish if you dont get on top of things

Dave

 

[MitchM]

.... yes have city water and have never treated it. ...

That's one red flag there.
What did your cleaning consist of and how much water did you change?

 

[puckerup]

That's one red flag there.
What did your cleaning consist of and how much water did you change?

We always empty the pond, remove the scum, etc. from the liner, rinse off rocks, plants. NEVER use chemicals, fish are carefully removed to a very large tub of pond water and carefully reintroduced back to new temperature of pond. But that was 6 weeks ago. Can something we did then still be affecting pond?

 

[MitchM]

It sounds like a number of factors; overstocked, too much cleaning of the pond, possibly not enough water circulation or filtration, not treating city water before refilling.

When you clean a pond too thoroughly, you can remove some of the bio-film that is responsible for the nitrification cycle that processes the waste that your fish produce.

When you don't treat your city water before you expose the fish to it, chlorine and/or chloramine will damage the fish's gills which will affect their breathing.

If you are finding dead fish mainly in the morning, it could be because they died from a lack of oxygen during the night, this could be from overcrowding plus any damage to their gills.

When you can provide the information that others have asked for, we can come up with what would be best to do from here.

 

[CometKeith]

Puckerup, sorry about your fish. It sounds like your bioload got too high. Typically dead fish in the morning is a clear sign of oxygen deprivation. I always go really slow in the spring. i don't over clean and just net the bottom for leaves. It's the worse time to introduce new fish or anything new because the immune systems of your fish are very low coming out of winter. You don't want to add anything that will add stress. Also i barely feed until my pond has cycled.Once it has cycled I know it will convert the fish wastes to inert substance but before then I go really slow. There are a number of "experts" that say pond cleaning should be done in the fall because your fish have built up their resistance and will not be as suseptible to bacteria that may get unleashed when you start cleaning. I know it's natural to do "spring cleaning" but it makes a lot of sense to wait.

 

[Dave 54]

Puckerup, sorry about your fish. It sounds like your bioload got too high. Typically dead fish in the morning is a clear sign of oxygen deprivation. I always go really slow in the spring. i don't over clean and just net the bottom for leaves. It's the worse time to introduce new fish or anything new because the immune systems of your fish are very low coming out of winter. You don't want to add anything that will add stress. Also i barely feed until my pond has cycled.Once it has cycled I know it will convert the fish wastes to inert substance but before then I go really slow. There are a number of "experts" that say pond cleaning should be done in the fall because your fish have built up their resistance and will not be as suseptible to bacteria that may get unleashed when you start cleaning. I know it's natural to do "spring cleaning" but it makes a lot of sense to wait.

I couldnt have put it any better myself Keith you touched on all the points I wished to make and hopefully this will be taken on board by the poster himself.
But keep in mind the areomonas bacteria when cleaning or your gong to loose fish hand over fish so to speak

Dave

 

[puckerup]

There are a lot of people here who know a heck of a lot more than me, but to start, some questions.

What were the other water test results?

What sort of filter system do you have? Pump size?

How deep is your pond? Is it in the sun? What zone are you located in? (or just location)

How big are (were) your fish?

Did you quarantine your new koi before introducing them?

What time of day did your fish die?

A 280 gallon pond is pretty small, and it sounds like you had too many fish. And that size pond is definitely too small for koi. They may be small when you buy them, but they grow fast. Also, when you're experiencing unexplained fish die-offs, that is definitely not the time to add more fish to your pond. I'm not trying to scold you after the fact, just pointing this out so that you don't add more while you're trying to figure out why the fish you have are dying.

We no longer have the box but husband said pump is "powerful"
Test results this AM-NITRATE (NO3) 0
" (NO2) 0
HARDNESS 25
ALKALINITY 0-40
PH 8.0-8.5
Pond is 2ft 4inch deep, 8ft long, 4ft wide
Fish ranged in size from 3-5 inches
Did not quarantine Koi
I am finding the fish dead in the morning.
Will try to include a photo of the guy I found this AM Hmmm was unable to find how to do this. Came someone pls give me instructions on how to add a photo here?