Help 7 fish is dead

[Alon Y amin]

Hi,
I have 1000 gallon pond with goldfish and koi fish in it,
For the past weeks a lot of fish in my pond started dying and in the past month something around 7-8 fish died.
The weird thing is only goldfish are dying the koi’s looks fine.
I have to mention that this started after I brought 10 new very little goldfish to the pond but they still alive and the other fish is dying.
I’m posting some photos of the dead fish, what should I do?

 

[Mmathis]

Hi, Alon! Haven’t heard from you in a while, but so sorry that you’re having problems. Thank you for posting pictures.

Not sure what to tell you, as it sounds like you have several issues going on, and there often isn’t a single cause or a simple way to fix it. Mostly, there are things you can do to prevent future problems.

1. Have you been doing water tests? Can you tell us the results of those tests (ammonia, nitrites, nitrates, pH, KH, GH, and oxygen level if you have access to this test) — the actual results in numbers?
2. Your pond is 1000 gallons (or 4000 liters as you posted a while back). How many TOTAL fish do you have, how many of these are koi, and how big are they?
   
3. What kind of filtration do you have? Do you still have the waterfall?
4. Have there been any chemicals or contaminates that could have gotten into the water?
5. Did you quarantine your new fish?

THINGS TO CONSIDER:

1. You might be overstocked (more fish than your filtration and pond size can handle)
2. You added new fish recently (which added to overstocking, and may have brought parasites into the pond if those fish weren’t quarantined)
3. From the pictures, there doesn’t appear to be any outward signs of disease or injury (but I’m not an expert)

WHAT CAN YOU DO NOW?
I will let other members answer this one. All I can think of is to

1. reduce your fish population (which Mother Nature has already done)
2. Do some water changes
3. If you have access to a microscope, you can scrape and scope a few of the living fish to check for parasites
4. Be sure you have adequate aeration and filtration
5. Consider this a learning experience (I don’t mean to sound cruel, but this IS how we make things better for the future).

 

[Alon Y amin]

1)
PH- 7.6
High range PH- 8.2
Ammonia- 0
Nitrite - 0
Nitrate- 5 ppm

2) I have 2 big koi and the other ones are around 20cm the two big are 40 cm.
I have a total of around 25 fish in the pond.
3) I have a big diy filter with lava rocks that spills to the waterfall and then drops to the water.
4)I really don’t know, there some plants near the pond but I don’t think maybe because of couple leaves this could happen I will pose a photo.
5) I did not quarantine the new fish but they still living in the pond and the other fish are dying which is very weird.

Hi, Alon! Haven’t heard from you in a while, but so sorry that you’re having problems. Thank you for posting pictures.

Not sure what to tell you, as it sounds like you have several issues going on, and there often isn’t a single cause or a simple way to fix it. Mostly, there are things you can do to prevent future problems.

1. Have you been doing water tests? Can you tell us the results of those tests (ammonia, nitrites, nitrates, pH, KH, GH, and oxygen level if you have access to this test) — the actual results in numbers?
2. Your pond is 1000 gallons (or 4000 liters as you posted a while back). How many TOTAL fish do you have, how many of these are koi, and how big are they?
   
3. What kind of filtration do you have? Do you still have the waterfall?
4. Have there been any chemicals or contaminates that could have gotten into the water?
5. Did you quarantine your new fish?

THINGS TO CONSIDER:

1. You might be overstocked (more fish than your filtration and pond size can handle)
2. You added new fish recently (which added to overstocking, and may have brought parasites into the pond if those fish weren’t quarantined)
3. From the pictures, there doesn’t appear to be any outward signs of disease or injury (but I’m not an expert)

WHAT CAN YOU DO NOW?
I will let other members answer this one. All I can think of is to

1. reduce your fish population (which Mother Nature has already done)
2. Do some water changes
3. If you have access to a microscope, you can scrape and scope a few of the living fish to check for parasites
4. Be sure you have adequate aeration and filtration
5. Consider this a learning experience (I don’t mean to sound cruel, but this IS how we make things better for the future).

 

[Tula]

It's not unusual for the fish residing in your pond to get sick or die, when newcomers are added. They've been a "closed society" of sorts and have no immunity to what the new fish bring with them.

I'm sorry for the loss of your fish.