Sick fish?

[Magzire]

Few days ago I bought two Shubunkin and two Koi. All are 3-4"

First day they seemed okay, swam around and ate some.
Now the two Koi and one Shubunkin (he barely moves, and seems to be breathing heavily) hide all the time, never see them eat. While the other Shubunkin is flourishing, chasing and eating.
I only have a liquid ammonia test that reads the lowest it can. I put 2.5kg of pond salt into a 1800l pond. Hopefully help with stress.
I don't understand how one new fish is doing great and the others look half dead. All the older fish have no problems and all look healthy, just the new ones.

 

[Magzire]

Could chlorine cause this? I have a 5 litre container with 1kg of Sodium thiosulphate that I made last year.
Maybe it lost it effectiveness?

 

[Meyer Jordan]

Where there already existing fish in the pond?

 

[Magzire]

Where there already existing fish in the pond?

Yes, there are 3 blackmoors, 6 goldfish and 2 Shubunkin, 1 koi.

 

[Magzire]

I forgot two mention, the two large Shubunkin got very aggressive in spawning. I had to take them out, the goldfish were getting hammered.

Maybe thats why the koi are hiding. However the Shubunkin does look sick

 

[Meyer Jordan]

A lot has been written about the importance of quarantining newly purchased fish before introducing them into a pond with an existing fish population. This protects the existing fish from newly introduced pathogens.
But what protects the newly purchased fish from pathogens already in the pond that they may not have any immunity to. Then,additionally, they have gone through the stress of handling and transport (the number 1 stressor for pond fish) which lowers their immunity.
I wonder how many pondkeepers actually quarantine new fish and how many of those do it using the existing pond water to test their immunities.
I suspect, in this case @Magzire, that stress is indeed a factor. If so, the fish will soon return to normal behavior.

 

[Magzire]

Thanks Jordan, some new knowledge there for future ponding.

 

[Magzire]

Finally found where the Koi where hiding, a small fold in the liner. Other than being scared them seem fine actually, they can move when they want to. Its just the Shubunkin I am worried about now.

 

[Magzire]

Here is the sick one, he will stay like that for hours without moving.
Is there any hope for him? I feel helpless.

 

[Meyer Jordan]

There is always hope! Just don't get so desperate that you start throwing various treatments in the pond without knowing exactly what may be wrong with this fish. As with most things concerning a pond, patience is a requirement.
Let's wait to see if this fish manifests any additional symptoms other than lethargy.

 

[MitchM]

Were the fish acclimated to the new environment before you put them in?

 

[Magzire]

Were the fish acclimated to the new environment before you put them in?

I placed the bags on top of pond for 30 mins and slowly let water into the bags, then released.

 

[MitchM]

I placed the bags on top of pond for 30 mins and slowly let water into the bags, then released.

That should be good then, depending on how different the two water parameters were.

 

[Lisak1]

But what protects the newly purchased fish from pathogens already in the pond that they may not have any immunity to.

I've often had that same thought - it's important to know you aren't putting sick fish into your pond, but how will the new environment affect the added fish? I guess it's not unexpected that a few fish won't handle the transition well.

 

[Magzire]

He didn't make it. The koi seem okay still, just very timid. Only come out at night.