pH crash???

[PapaBear]

In can't speak for Jnorth, but my first thought upon hearing you had lost all your fish was how terrible to lose such a beautiful Koi that way. Glad to hear at least your avatar fish is safe and well.
I've never heard of such a steep drop. Stumbling around in the dark as to possible causes since the Qtank is sheltered from outside contaminants. Your Biological filtration should have been well matured since it was from your old pond, but it could be that the mineral content became rapidly depleted making the water vulnerable to a severe drop. That possibility in combination with the antibiotics possibly killing off your bio could explain what happened, but I'm just guessing.

[kiky]

What a sad loss Moscine. I know you have a lot of koi kept at Samurai. Why didn't you also keep those in the q-tank at your dealer in Jkt. Building a new pond will take about 2-3 months. And it's too long a time for the koi to be in a q-tank waitng for the new pond.

You have my sympathy; but I have no idea what caused the Ph crash.

[johnsmith]

Mmm, 84 F water temps--- 10 fish between 20-28 inches in about 1000 gallons of water. In warm water.
The antibiotic also is a challenge to the biofilter. And the presence of fungus tells us the fish were stressed as fungus won't grow on health fish slime coated skin. They have immune system action within that slime coat against fungus, normally. The salt could help or it could hurt depending on conditions and the bigger picture?

Was the water green? I think the fish likely produced way too much carbon dioxide for the buffering capacity of your Qtank. I suspect that the struggling biofilter ( exposed to antibiotics) likely contributed to the oxygen depletion content as well. If the water was green, that also plays havoc with the buffering capacity and decay ( oxygen depletion again) in such a stocked system. All of this leads to a crash in pH values.
Normally in stocking situations like this I would suggest 20-30% water changes twice a week- especially at those temperatures. No feeding was a good idea. In the future add more aeration and try never to treat fish at those stocking levels unless it is with something like dimilin or PP as a bath and then a significant water change.
Again, very sorry for your loss but don't give up or let a wipe out turn you away from the hobby. You are going to be a better koi keeper from this painful experience.

[monscine]

Quote: Originally Posted by kiky What a sad loss Moscine. I know you have a lot of koi kept at Samurai. Why didn't you also keep those in the q-tank at your dealer in Jkt. Building a new pond will take about 2-3 months. And it's too long a time for the koi to be in a q-tank waitng for the new pond. You have my sympathy; but I have no idea what caused the Ph crash.

Thanks a lot for your sympathy. I wish I could send those koi to the dealer where I rent a pond on his farm. Unfortunately he refused other kois other than the ones which bought from him. I could understand this so I kept the kois on a small quarantine tank. Yeah, what a loss and I came to one point where I'm thinking of quiting this hobby cause I couldn't see my kois just died like that though I tried to give first aid to them...but useless

[monscine]

Quote: Originally Posted by PapaBear In can't speak for Jnorth, but my first thought upon hearing you had lost all your fish was how terrible to lose such a beautiful Koi that way. Glad to hear at least your avatar fish is safe and well. I've never heard of such a steep drop. Stumbling around in the dark as to possible causes since the Qtank is sheltered from outside contaminants. Your Biological filtration should have been well matured since it was from your old pond, but it could be that the mineral content became rapidly depleted making the water vulnerable to a severe drop. That possibility in combination with the antibiotics possibly killing off your bio could explain what happened, but I'm just guessing.

Your thinking of the antibiotics also came to my mind and I'm also consider it as the main reason...

[monscine]

Quote: Originally Posted by johnsmith Mmm, 84 F water temps--- 10 fish between 20-28 inches in about 1000 gallons of water. In warm water. The antibiotic also is a challenge to the biofilter. And the presence of fungus tells us the fish were stressed as fungus won't grow on health fish slime coated skin. They have immune system action within that slime coat against fungus, normally. The salt could help or it could hurt depending on conditions and the bigger picture? Was the water green? I think the fish likely produced way too much carbon dioxide for the buffering capacity of your Qtank. I suspect that the struggling biofilter ( exposed to antibiotics) likely contributed to the oxygen depletion content as well. If the water was green, that also plays havoc with the buffering capacity and decay ( oxygen depletion again) in such a stocked system. All of this leads to a crash in pH values. Normally in stocking situations like this I would suggest 20-30% water changes twice a week- especially at those temperatures. No feeding was a good idea. In the future add more aeration and try never to treat fish at those stocking levels unless it is with something like dimilin or PP as a bath and then a significant water change. Again, very sorry for your loss but don't give up or let a wipe out turn you away from the hobby. You are going to be a better koi keeper from this painful experience.

Thanks for your enlightment John and your symphaty. The water wasn't green at all as long as I put the kois on the quarantine pond. And again as PapaBear said, I'm rather agree the cause was the antibiotics.

[junglegeorge12]

Quote: Originally Posted by monscine I did some medication of fungus to the kois JR. As my 1st medication was success, then I did the same method to cure them but the result was out of my thought. All the kois were in quarantine tank which made of PE (I think) and lately there was no rain at all and even if there was, the rain wouldn't get to the tank directly cause I put the tank in an area with canopy. There was volcano activities far faraway from where I'm staying. But I don't see any relation between volcano activities with what happen to my kois.

I am sorry for your losses, I would suspect the meds firstly then other things. How long were they on this no feed regime? Of course you relaize that extended fasts in warm water will fatigue them and weaken them. I have seen koi have the same response to Melaflix and other meds when used according to directions, when used at half strength it seems to work just as good, but no mortalities.

A volcanoes can have an affect because the ash it releases contains sulfuric acid, which can plummet ph if a rain comes or a cloud of the ash comes in contact with the pond. That cloud may be invisible to the eye but might affect your allergies or breathing if dense enough. Not sure how far away you were or if a could of it may have drifted right over your pond and put the ash in contact with the water. Either way, it is sad to hear of such losses. It is a good thing your dealer did not let sick koi into his facility, then you might not be able to even buy replacements...

get back on the horse and ride, you love koi and this isn't your fault, if the treatment didn't kill them the ilness would have. Next time maybe make sure of more air and a different treament method is all. Tough and possibly quite expensive lessons. I don't think there is anyone here who has not lost a koi.