6 goldfish dead- only 4 left- HELP Please

[DiZee]

Good morning all,
My pond is 750 gal with a box bog filter. I have had it for 4 years now with no problems. Lat fall 4 fish died (one my only koi), this year the trend has continued 6 died already. Scales are patched with white, no fuzz. Like color missing. No pineconing. Fish just sit around, and don't eat before dying. No gulping for air.

Went to my local pond store yesterday with sick fish. He gave me Microbe Lift BSDT I did 25% water change (as he tested my water and ammonia was a little high(not bad though) all other readings were in good range. So added Beneficial Bacteria, as recommended. Put in 1 dose of BSDT.
Now what? What will I be looking for? Do I do another water change or not?
What would you do?

 

[Lisak1]

Welcome @DiZee ! Sorry that it's pond troubles that brought you here.

I'm not a fish health expert, but someone will have some good advice for you. Lots of knowledge and willingness to help here!

One thing I would comment on right off the top of my head - you have already lost 10 fish including one koi. How many more fish are in your pond? 750 gallons is a smallish pond - perhaps you just had too many fish.

As far as the beneficial bacteria - I'm not sure why they think that will help with sick fish. Did they offer any conclusions as to what might be causing the problem? And you say the ammonia was "a little high" - do you know the number? Ammonia above 0 is indicative of a problem. Knowing the actual readings from the testing would be very helpful!

 

[MitchM]

After 4 years, if your fish died I'm thinking you have either a severe water quality problem or something got into your pond. Goldfish are very hardy fish.
Can you post more information, like what you have for filtration and what the numerical test results were?
Also, stop adding anything to the pond until the specific problem is identified.

 

[Mucky_Waters]

As far as the beneficial bacteria - I'm not sure why they think that will help with sick fish

That was my first reaction when I read DiZee's post as well, but a quick search on Microbe-Lift with (BSDT) revealed that it has other stuff (malachite green and formalin products) that work as a Broad Spectrum Disease Treatment and might be useful in this case, although I question the usefulness and wisdom of buying them combined with a "beneficial bacteria" product. It seems to me if there was really any live viable beneficial bacteria in the product at all, that the addition of formalin, a strong antiseptic, would quickly kill off any viable beneficial bacteria that might be contained in the product.
However, it would likely still be just as effective at beneficial bacteria enhancing your pond as buying a beneficial bacteria product that didn't contain any bacteria killing product like formalin.

https://www.microbelift.com/product/broad-spectrum-disease-treatment-bsdt/

 

[Lisak1]

Ah! Missed that part!

 

[Mmathis]

Hello and welcome! Sorry that you are having problems. That always sucks, but I’ve learned that the best thing to do is discover the source of the problem and try to resolve things one issue at a time.

Your pond is 750 gallons. How many fish do you have and are they all koi? Have you added any new fish lately? It does sound like you might be overstocked. Even if you’ve only had the same fish for the past 4 years, they are going to grow and just their growth will add to the amount of waste products.

Do you have any pictures of your pond, and/or pics of the fish?

 

[sissy]

Do they have aeration with the heat we were getting it is hard on fish lately and do you test your water