baby fish found dead is something wrong?

[Dave 54]

@Dave 54 I didn't get the impression that the OP was necessarily trying to breed the fish (Shubunkins, from the sound of it) but that they "just happened," and now some of those fry are dying off, etc. and he's wondering why...... I think some of those possible reasons have been covered (normal attrition, canibalism, pond predators......to name a few).

He has had fry before, but [apparently] has never has a die-off like this before. I can't help but wonder about the problems he was having with the pond back a month or so ago, and wonder if that has anything to do with this? I think there was some question as to whether a chemical agent accidently got into the pond and was killing the mature fish vs. general water quality issues [over-crowding]. Even though he's cleaned the pond, what if there were chemicals present initially.... Would they have all been removed by a cleaning? Would filter media be harder to clean from that standpoint? And what about the chemical effects on the parents possibly causing "genetic" type issues? Not saying this is what's going on [I thinks it's normal attrition, etc.], but you do have to keep the HISTORY of this pond in mind.

Agreed Maggie but water quality may well still be an issue whilst the OP still uses dip test kits as we both know they arent that accurate at the best of times .
It may well be chemicals still but who really knows not until we get the whole picture and perameter readings from a reliable drop test kit .
The OP knows how well the pond was cleaned if the OP says it was well cleaned as was the filter then I cant see that being a problem can you ?

Dave

 

[Meyer Jordan]

The results gleaned from a typical test kit will not reveal chemical pollutants. These are specialized test that are conducted using special testing equipment. Moreover, at this point is time, any chemical residue that may have been present has long since dissipated. A chemical cause for the fish loss can now only be treated as speculative. The chance for proving yea or nay has long since passed.

 

[Dave 54]

Very familiar with the process that you described


This statement is what is at issue. What you feel are optimum conditions clashes with what Koi breeders and hatcheries feel are optimum conditions for immediately after hatching the fry are transferred to mud ponds which are highly eutrophic and rife with all of the organisms common to natural ponds, including pathogens. duplication or approximation of a natural environment together with a natural diet is proven to be optimum.

LOL: oh you slay me Meyer where the heck do you think we live, this is the UK my friend not the wide open spaces of the US
If many of us in the koi world had the land in our back yards to stick in a mud pond we would, sadly my friend this is the old world its rather crowded as such we live cheek by jowel .
Jeff had to build a retaining wall then move 5 tonnes of soil rock and shillit just to get a 1,000 gallon pond in it with room to walk around, you might be able to build one we certainly cant nor can many others in the UK .
As such the owner breeder releases the young koi back into the pond at a size they wont be eaten its the same in the mudponds they only go in at a certain size to maximize profit at the end of the growing on period.
This is taking us away from the OP's original question and I dont want to hijack it .
Lets get back to answering the OP's questions before folks think we are going tit for tat at each other, we are talking garden ponds, not mud ponds.
We will have to agree to disagree My friend

Dave

 

[Mmathis]

The results gleaned from a typical test kit will not reveal chemical pollutants. These are specialized test that are conducted using special testing equipment. Moreover, at this point is time, any chemical residue that may have been present has long since dissipated. A chemical cause for the fish loss can now only be treated as speculative. The chance for proving yea or nay has long since passed.

Then how come there are chemicals that last for years, that make people sick (or kill plants/wildlife) for years afterward.... To know a half-life, you'd have to know what the chemical was. Just saying.....

 

[Meyer Jordan]

Then how come there are chemicals that last for years, that make people sick (or kill plants/wildlife) for years afterward.... To know a half-life, you'd have to know what the chemical was. Just saying.....

You are absolutely correct. There are chemicals that persist. Generally speaking, the over-the-counter variety of pesticide and herbicide is not meant to last very long (That's how they keep sales figures up).
Discovering exactly what chemical may be creating a toxic condition requires extensive laboratory testing using specialized equipment. There are commercial labs that will do a series of tests for about 180 different toxic chemicals. These series of tests are not inexpensive and, considering the fact that there are hundreds, if not thousands, of chemical substances in use, the results of these tests may not reveal very much pertinent information.
If anyone is interested in the half-lifes of some of the chemicals in use, see-
http://npic.orst.edu/ingred/ppdmove.htm

 

[Mucky_Waters]

I have the shubunkins and earlier this year I lost 7 of my fish, , now so far all seems well. They had babies, but now I seem to be finding them dead. Not all of them but a few were dead, and not sure why. A couple of them looked injured. Any one have any ideas? This is the first time I have seen so many of the babies. When I find them they have been about half inch and smaller.

Not sure what type of filter system you have water circulation system, but my first guess would be that perhaps some of your little fry got sucked through your pump and spit out the other end. Some died and some were injured.

 

[Mmathis]

Not sure what type of filter system you have water circulation system, but my first guess would be that perhaps some of your little fry got sucked through your pump and spit out the other end. Some died and some were injured.

I hadn't thought about that!

 

[Meyer Jordan]

I failed to mention (and apologize for the omission) that usually the soil half-life of a chemical is all that is offered. This time period may vary greatly from the half-life in water (hydrolysis half-life). In many cases the hydrolysis half-life is considerably less than the soil half-life. Other environmental factors may come into play affecting the half-life of a chemical- sunlight (UV), aerobic/anaerobic conditions. pH etc.
Consider Permethrin for example-

"Each pesticide can have many half-lives depending on conditions in the environment. For example, permethrin breaks down at different speeds in soil, in water, on plants, and in homes.

-- In soil, the half-life of permethrin is about 40 days, ranging from 11-113 days.
-- In the water column, the half-life of permethrin is 19-27 hours. If it sticks to sediment, it can last over a year.
-- On plant surfaces, the half-life of permethrin ranges from 1-3 weeks, depending on the plant species.
-- Indoors, the half-life of permethrin can be highly variable. It is expected to be over, or well over, 20 days."

National Pesticide Information Center

So, not only is the identification of a suspect chemical complicated, even after an identification is made, the half-life must be determined which can be as complicated.

 

[Mmathis]

@Meyer Jordan Oh, my! And just when we thought it was safe to go back in the water......

 

[Meyer Jordan]

@Meyer Jordan Oh, my! And just when we thought it was safe to go back in the water......

Yes, it can be dizzying contemplating all of the things that can cause problems in a pond.