Help please.

[Magicno1]

I live in the UK.

I have lost 3 fish in the last week with what looks like ulcers and skin blemishes with red marks.
My pond was built 14 months ago and is around with around 7000 litres. It is fed via a bog filter spilling back into the pond which is full with pea gravel about 10” and lots of healthy plants and is about quarter the size of the pond.
I have around 20 fish in there 10 being 5-6” koi and the rest small goldfish.
My tests are:
PH 7.5
Nitrite 0
Ammonia 0
Phosphate 1
GH KH 14 too high?

My 10000 Oase pump has two inlets. Pump is at the opposite end to the spill with a satellite strainer the spill end.
One outlet goes to the bog the other goes into the pond via an aerator for oxygen and movement.

I feed once daily sometimes every other day but only enough for a couple minutes.

I don’t have a Nitrate kit

The pond has stone lined walls and Scottish pebbles on the bottom which I know most don’t like but I clean by pond vac every few weeks.

Most of these fish have been moved from my old pond and were happy for years so now I’m getting worried I’m going to lose them all so any help much appreciated!
Chris

 

[JRS]

Bacterial infections usually are byproducts of poor water quality or secondary to a parasitic infection. You say most were old-any new additions lately that might have brought a pathogen in?

Have you found any disease pictures online that look like your fish?

 

[GBBUDD]

are you using a dechlorinater

 

[Magicno1]

About 9 were introduced about 7 weeks ago.
Yes I use a dechlorinater.

 

[Mmathis]

I suspect water quality issues.

What kind of water test kit are you using? We recommend a liquid test kit (such as API Master Freshwater kit). Then, you have to add the tests for KH and GH.

It looks like your pond is just on the border of being large enough for koi….even though yours are still small.

Have you done anything different recently? Such as added new fish?

 

[Magicno1]

I suspect water quality issues.

What kind of water test kit are you using? We recommend a liquid test kit (such as API Master Freshwater kit). Then, you have to add the tests for KH and GH.

It looks like your pond is just on the border of being large enough for koi….even though yours are still small.

Have you done anything different recently? Such as added new fish?

I use that kit!
Apart from the new fish a couple months back all I’ve done last week was add some more plants to the bog.
I vacuum the pond once a month and replace with dechlorinated water.
‍

 

[Magicno1]

I’ve a new Columbo test kit arriving tomorrow to cross check results and I’ll report back again.
It’s really gutting and now I’m worried I’m going to lose them all!
I get lots of conflicting views on bog filters and rocks on the bottom holding bad bacteria and also benificial bacteria too!
I will be adding a new filter box with another pump shortly so we’ll see if that helps with removal of crud.

What ideally would GH and KH be????
And if too high I presume it can be adjusted with additives?

 

[Mmathis]

I can’t give you ideal results off the top of my head (it’s been a while since I tested), but the instructions that come with the kit should have this info. I want to say that you want the KH to be at least 100, with the higher being better. Others will have to advise regarding treatment. I run a low KH, so I have crushed oyster shells integrated into my filter.

Keep this in mind about ANY treatments you do to in order to make a change: only try to change/adjust one thing at a time. Too many people jump in and try to change everything all at once — this is not good. MAKE ONE CHANGE AT AT TIME!

Again, not the one to be giving advice, but if your water tests are correct, everything looks OK, except: is the KH the corrected result…..or is that how many drops you added to get to that result? I usually multiply the number of drops by 18 to get the final result.

 

[Magicno1]

I can’t give you ideal results off the top of my head (it’s been a while since I tested), but the instructions that come with the kit should have this info. I want to say that you want the KH to be at least 100, with the higher being better. Others will have to advise regarding treatment. I run a low KH, so I have crushed oyster shells integrated into my filter.

Keep this in mind about ANY treatments you do to in order to make a change: only try to change/adjust one thing at a time. Too many people jump in and try to change everything all at once — this is not good. MAKE ONE CHANGE AT AT TIME!

Again, not the one to be giving advice, but if your water tests are correct, everything looks OK, except: is the KH the corrected result…..or is that how many drops you added to get to that result? I usually multiply the number of drops by 18 to get the final result.

14 drops I counted for the colour to turn.
I may have worked the end figure wrong!

 

[Mmathis]

That should be a good number. What are the expiration dates on your test kits?

 

[Criscar]

I live in the UK.

I have lost 3 fish in the last week with what looks like ulcers and skin blemishes with red marks.
My pond was built 14 months ago and is around with around 7000 litres. It is fed via a bog filter spilling back into the pond which is full with pea gravel about 10” and lots of healthy plants and is about quarter the size of the pond.
I have around 20 fish in there 10 being 5-6” koi and the rest small goldfish.
My tests are:
PH 7.5
Nitrite 0
Ammonia 0
Phosphate 1
GH KH 14 too high?

My 10000 Oase pump has two inlets. Pump is at the opposite end to the spill with a satellite strainer the spill end.
One outlet goes to the bog the other goes into the pond via an aerator for oxygen and movement.

I feed once daily sometimes every other day but only enough for a couple minutes.

I don’t have a Nitrate kit

The pond has stone lined walls and Scottish pebbles on the bottom which I know most don’t like but I clean by pond vac every few weeks.

Most of these fish have been moved from my old pond and were happy for years so now I’m getting worried I’m going to lose them all so any help much appreciated!
Chris

Are the fish dying the new fish, the old fish, or a mix of both? Did you quarantine your new fish before introducing them to the pond and if so did any issues crop up at that time?

 

[Magicno1]

Mix of both. No I didn’t quarantine

 

[Criscar]

Mix of both. No I didn’t quarantine

Have you noticed any odd behavior like a lot of flashing (rapidly darting around), rubbing on things, clamped fins? Or any change in appearance prior to the appearance of the ulcers, like little white spots or strings, or small little greenish-brown discs on them?

 

[Magicno1]

Have you noticed any odd behavior like a lot of flashing (rapidly darting around), rubbing on things, clamped fins? Or any change in appearance prior to the appearance of the ulcers, like little white spots or strings, or small little greenish-brown discs on them?

There has been one or two that do dart around yes. The only change to skin I noticed was the first one that died which had a load of white blister like patches/ ulcers on his body and white fins

 

[Lisak1]

Oh I’m sorry! These things are so frustrating. I would agree it’a either water quality or an introduced pathogen… or both. Not helpful I know, but adding new fish is always putting you at risk of either.

Do be aware moving forward that your pond at 1800 US gallons isn’t ideal for koi. Goldfish are a much better choice.