I lost 3 fish to my stupid error..please read!!

[Brutuscz]

This is a picture of my pond and a close-up of the waterfall. The water only falls about 15 inches...not too high. But I dont live on a mountain..lol!!

[keokoi]

Are those Rocks on Bottom of pond?

[Brutuscz]

No..smooth bottom...just liner.

[Arthur]

Brutus,

I read the whole thread and I have to ask: when was the last time you THOROUGHLY cleaned the bottom of your pond?

In the pictures I do not see much circulation at all and without that and no bottom drain, organic debris will accumulate on the bottom.

The decaying debris would steal oxygen and release carbon dioxide in the water. What is your pH (morning, noon, and evening), what fluctuations?

This situation (if true) would create anaerobic condition that would foster parasites and bateria developments; if really bad, possibly hydrogen sulfide.

I would encourage you to get a gill snip under the microscope and look for hypersplasia and parasites. If you do not know how to take a gill snip, do a scrape around the gill plate, that's the next best.

Like everybody else that offered help here, I do not believe a DO of five to kill fish, simply slows them down and reduces appetite. Something else is at work here and you must find what it is.

Introducing a new fish even quarantined can cause problems. Three things can happen:
1) all is fine :-);
2) the new fish gets sick;
3) the old fish get sick.

2) and 3) can happen because fish have their immune systems tuned to the environment they live in. Both the old fish and the new may be perfectly healthy before the change. The stress of the change may cause the new fish to start up a parasite infestation that will get to the old fish, or carry parasites that its immune system is used to and pass them on to the old fish that do not know quite how to handle them (yet).

You have to look for what is actually causin the problem.

Sorry for the long post but I wanted to give you good reason to scrape and search.

[dtbh]

I am no expert but I will try to analyse this problem the way I usually do.

FACT 1 : Many bigger fish died which suggest that all the fish were/are exposed to this and as you rightly suggested may be related to O2 demand. Bigger fish have higher O2 demand and as such they are more susceptible. Is this due to low water DO or is this due to poor O2 absorption by the gills? You mentioned some gill discoloration which strongly suggest a gill problem (cause?) This leads me to FACT 2.

FACT 2 : You have added new fish. A piece of advice here. NEVER ever add new fish without doing your own quarantine protocol no matter how reliable is the dealer/fellow hobbyist. Too many accidents had happen that way. Many of us have experienced parasitic infestation after adding fish from good hobbyists whose fish are perfectly healthy. Signs of parasitic infestation that involves the gills that I know include listlessness, poor apetite, crowding around higher O2 saturated areas, hanging almost vertically head down at the surface.

FACT 3 : You had DO at 11 to 12 (I would assume the water must be very cold then at this level) in which case I would expect your O2 generating capacity is good. What are you using to provide for O2 generation? I don't think moving a water pump will actually reduce the O2 saturation; if anything it will affect O2 distribution ie certain areas will be good. The kois will accumulate in the good areas and in your case the waterfall. What is the O2 level near the waterfall?

I don't think your kois died because of a DO of 5 eventhough this is no doubt a contributing factor. Moving the pump is probably just a red herring. I suspect your DO at certain parts of your pond has been hovering around this level all along for the past 5 years during hot weather but your healthy kois were able to tolerate it by moving to higher DO areas in your pond. I would place my bet on some form of parasitic gill disease the source of which is the new koi you added.

What I would do when faced with this situation :

1. Increase DO. I would just add an air pump (and not use hydrogen peroxide) as it is a more permanent solution and less stressful on your already stressed kois.
2. Stop feeding
3. Try to identify parasite (if any) and treat
4. More vigilant management of filter esp during this crisis without further stress on your kois
5. Measure DO at various areas of the pond including the filter.

I am really sad for you. I hope this will help.

[Brutuscz]

I really appreciate the help. In april, I removed all the fish, and placed a new liner in my pond. Some branches that fell had punched holes in my old liner and it was leaking. The holes were too big to repair, so I relined the whole pond. Because of this, there was no residual debris from last fall. The bottom of my pond is pretty clean. I have no rocks or gravel. I scoop the bottom clean regularly with a large net. It seemed with the surface skimmer, that not much dirt was reaching the bottom. The skimmer was working wonderfully. I am pretty serious about having clear water and a pond that looks clean. Since you think parasites may be an issue, do you think I should salt the pond? I have in the past, and I have a kit to measure it properly. I was just concerned that salting would lower my DO. I know everyone is saying a DO of 5 shouldn't kill fish, but I believe it may have been low for a month or so. When the big fish initially started to act funny (stop eating, stay near the waterfall, breath heavily) I thought they were getting ready to breed!!! It never occured to me that something was wrong. I threw in spawning mops, and set up a 500gal tank to raise the fry!! Man was I waaaay off. Anyway, let me know what you think about salting...thanks again.

[jnorth]

Quote: Originally Posted by Brutuscz Anyway, let me know what you think about salting...thanks again.

Salting doesnt kill a whole lot of bugs and can reduce the effectiveness of some treatments. What you need to do first is use a microscope and find out what bugs you have. Then you can determine the best treatment based on the type of parasites present. If you don't have one or don't know how to use it then I would suggest contacting your local Koi club and ask them for help. Most Koi clubs will have someone available to help you with a scope.

[greg]

Brurtuscz,

Looking at your pictures i notice no water movement from air stones or Aqaufusers. Turned off??? Or is the waterfall your only means of adding air?

If your Koi are struggling for O2 surely in my inexperianced view adding more air even as a temp measure is a must. I have been advised that i should be adding a minimum of 20lpm per 1000g but my target figure is more like 40lpm.

My new pond when complete will be approx 5000g including filters and i will be adding 240 lpm of air via Airtech pumps and aquafusers to my pond and filters.

In the UK we notice that Koi really struggle on humid thundery nights for O2 - is it like that were you are??

And has already been mentioned up your filter cleaning - currently doing my current pond (similar to yours) twice a week with a 5% water change also.

Keep us updated,

[hwong]

Hi Brutus,

I recalled a posting on the Malaysian Koi forum quite some time back. A singaporean koi keeper also experienced this phenomenon. His Kois were dying with no obvious reasons. Later he found out that the local water authorities had began adding chloramine to disinfect the tap water which is his source of supply. His usual dechloro does not neutralise chloramine which does not dissipate like chlorine. MAybe you shud look into this possibility. Here is some info on chloramine http://faq.thekrib.com/begin-tapwater.html

[dcny]

If you believe DO is the problem then you can temporarily put in some sort of spray bar. Basically it's just a length of pvc pipe with holes drilled in it, power by some pump. Direct it at a 45 degree angle into the pond.

It's possbilbe that when you moved our submersible pump, you disturbed some of the decaying debris that Arthur described excerbaing the situation.

I'm sorry for your losses and good luck managing your situation.

-Dan