I messed up - trying to determine when pond will be safe again

[kgliner]

Hello,

I have a 2500+ gallon large backyard pond with pool size pumps and filters. I have been slowly adding new Koi over the last year since moving into house and they have done well. I only bought from those that sell Koi locally for a living.

A few weeks ago, A neighbor wanted to empty his pond and had some 18" + long KOI. His pond was not that clear and extremely frothy with foam on the surface. I took them and put into my pond (without isolating or treating them). They all died within a week and then all my own fish started dying off 1-3 a day. I assume the new fish had some type of disease (maybe parasites). All the fish that died looked normal when they died (i am no expert).

I am down to 5 fish and am trying to determine when is it safe to introduce more fish? Lesson learned on introducing new fish to the pond.

I did treat the pond once with PH powder (purple stuff). A week later i added Pro Form C 2 days in a row after draining part of the water first. Pro form says to do 3 days in a row. I Just did a water test today- High PH, No Nitrates, No Ammonia, a little Phosphate.

 

[mrsclem]

Quarantine is the only safe way to add new fish. You need to set up a seperate tank and isolate the new fish for at least 4-6 weeks. I'm hoping someone will start a thread as to guidelines for a good setup and how to run it.
How many koi did you have and how many did you add?

 

[Lisak1]

@mrsclem - here's just the thread you were looking for! Hopefully someone will chime in and help @paco with his quarantine set up!

https://www.gardenpondforum.com/threads/quarantine.23887/

 

[Tula]

If I were you, I'd not add any new fish.....I'd concentrate on the 5 remaining koi and stabilizing the pond water conditions.

 

[Lisak1]

Welcome @kgliner ! Glad to see you here, even if it is at a time of pond trouble - not that unusual actually!

I'm with @Tula on waiting to make sure these remaining fish will be OK. You had a bit of a catastrophe - taking a bit of time to let things settle down is probably a good idea.

Tell us a bit more about your set up - you say "pool sized pumps and filters" - what exactly does that mean? Are these filters designed for pools or ponds? Do you have more than one filter? How many total fish did you start with and how many of your neighbor's fish did you add? How long were his fish in his pond? At 18" I'm guessing they had been there for a while with no issues. A pond that's not clear and a bit foamy isn't necessarily a sign of unhealthy fish - maybe a pond that had been a bit neglected, but often that bothers the pond viewer more than the pond dwellers. It may have been a case of too much at once for both groups of koi when you combined them into one pond. But a bit more information would help.

 

[ShawnInfirmity]

That's what I was think @Lisak1 , might have simply been adding too many fish at once to a system that could have already been maxed out on bioload.

 

[kgliner]

I had about 30-40 fish ranging from 1-2 years old. i added 8 18" long 10 year old + fish. Pond is size of small pool about 2,500 gallons with 4 tiers. All fish were in lower tier which is about 30'x10'x 2' Deep

1/3 HP 1800RPM pump that runs 24/7
In line ultraviolet light
20k gallon media filter
2 pool pumps for water fall (for occasional use)
Pebble tech lined

This was all here and installed with no fish when i bought house last year

 

[Lisak1]

So almost 50 fish in 2500 gallons? There’s your answer. I think you tipped the scale. Your pond is too small for that many fish.

 

[mrsclem]

Totally agree with Lisak1, way too many fish. You have 5 koi which is a good number for 2500 gallon. Are you sure about size of your pond? 30x10x2 is over 3000 gallons.

 

[Mmathis]

Oh my!

 

[kgliner]

I could be off on my math. Someone told me I had 2500 total

 

[addy1]

Welcome to our forum.

I agree with the above, I think you pushed your pond over the fish limit.

 

[mrsclem]

Can you give us dimensions of both sections of ponds?