Koi... seasonal die-off? More likely poisoned by too much change, untreated source water   – 05/08/07
My finance and I recently moved into a rental with a pond in the backyard (We do not know the size nor the size of the pump-sorry). Last week, we noticed that the algae was getting pretty bad, so we took all the fish out (12 Koi, 1 turtle and 3 catfish), put them into tubs and scrubbed out the pond (no chemicals used).
<Not even something to remove the tapwater sanitizer?>
  Yesterday, the turtle and the catfish were fine (and still are), but all but 3 Koi were dead (as of this morning, only one is still living). Since we don't know the first thing about the fish (the landlord told us to feed them and that's all, saying that they take care of themselves), I want to see what can be done.
  We took all the catfish out and the turtle and put them into one tub, and the Koi into another one. We don't know if it is male or female, so "he" is floating towards the top, doesn't seem to be interested in food and is pretty still but still breathing. He is dark orange in color and do not notice any external problems.
  We drained out the pond again but the algae this time was worse than last week. We are not done cleaning it out yet (will be by this afternoon) and was wondering what we need to do help out our last surviving Koi. Do we keep him away from the catfish for now? And mainly could you help us try to find out what may be the problem so we can keep him?
  Thank you so much!
<Please read here: http://www.wetwebmedia.com/PondSubWebIndex/Pond%20Sub%20Web.htm
The trays below on Maintenance, Water... Bob Fenner>

Pond problems  9/15/06
Hi.  I came across your site on the web.  I am experiencing problems with my new Koi pond and was wondering if you might have any insight.
<Might>
My pond was built about 3 months ago out of bluestone with a standard liner.
<Standard? Not one made for swimming pool use I hope/trust... these are toxic>
It is a small pond, about 250 gallons (3.5 feet x 6.5 feet x 20 inches deep).
<Not large/deep enough to be stable-enough in most settings, climates>
We have a pump with a filter that circulates the water with a waterfall.  We have added plants -- water irises, parrot feather, water hyacinths and water lilies.  I have also been adding bacteria -- specifically in liquid form with a product called Clear Pond.  
<Yes... sometimes "works", often not>
About 3 weeks after the pond had been running, I added 2 small Koi to the pond.  One of the Koi died within 2 days.  I waited about 4 days and introduced 3 very small Comet goldfish.
<Mmm, would get/use test kits for water quality. Would not keep Koi in such a small volume, definitely would not mix goldfish and Koi>
  About 5 days later, 1 of the goldfish died.  Then slowly, over the course of the next week, each of the fish died.  We had the company who constructed the pond come out to test the water 3 times, and each time all of the levels (ammonia, nitrates, nitrites, ph, water hardness) were in normal range.  So, I waited a week, continued to add the bacteria and introduced 2 more small Koi.  They also died within 1 day.
<Something toxic...>
I called in another pond expert to get a second opinion.  He also tested the pond water and said everything looked fine.
<For what was tested>
  He gave me a better bacteria in granular form that he uses and told me to add a 1/4 teaspoon to the pond every day for 2 weeks and that he would then bring in a hardier Koi.  Well, 2 weeks past, he brought the medium sized, "hardier" Koi and it died with in 4 hours.
I am perplexed, as are all of our pond experts.  The one commonality is that all of the fish had glazed over/white eyes when they died.  
<Poisoned>
In fact, the last Koi's eyes were bulging out.  None of them were gasping for air or swimming at the top, therefore I do not believe it is an oxygen issue.  And the pond water is clear.
<"So is white vinegar"...>
Please help!  Do you have any idea what could be wrong with my pond, or could you give us any suggestions of what to check?  Thank you!
<I'd dump all the water out (leave the plants), re-fill, wait a week, look for a product called "Bio-Spira" for freshwater... add this, wait another week, and try whichever type of fish life you intend to keep again. I suspect that there is "something" that either was left in the original construction or consequently got into your system that was/is toxic. Please read here: http://www.wetwebmedia.com/PondSubWebIndex/pdenvdisfaqs.htm
and the linked files above. Bob Fenner>
 

Sick pond Koi possible poisoning ???   11/11/07
I have a 12-inch Koi that’s not doing well( I don’t think he’s going to make it). He has been outside in a pond for the last year. A few weeks ago something nasty got into the pond and killed off all the fish except him.
<Yikes...>
The water smelled like bug spray and was all foamy.
<I can tell you some incidents of such "over-spray" here in S. Cal. Does happen>
I have no idea what it was.
We drained the pond, cleaned it, refilled it, let the water mature and put the Koi back in the pond along with two new three inch Koi.
<Mmm, I do hope some of the biological filter capacity was preserved...>
Yesterday my dad said the big Koi was hanging around the top. I checked but he was hiding in his flowerpot. When I went to feed them today he was on the top and didn’t run when I picked him up.
<Not good>
All of his fins are bloodshot (hemorrhaging) and very stiff almost rigid. He can’t seem to stay upright very well and is gasping.
<Good description, bad signs>
His slime coat seams not to be almost nonexistent except a small amount around his head. His anus has some hemorrhaging around it as well as some small 1-3 cm patches of hemorrhaging in other various places on his body. He follows me with his eyes so I know he can see me but he just isn’t able to react. I have no idea what could have caused an otherwise healthy fish to suddenly turn south like this practically overnight. Unless whatever got into the pond poisoned him as well & he’s just taking longer to react to it because of being so much larger than his other pond mates were.
<This is likely the case>
The two new Koi are doing fine. No signs of whatever is affecting the larger Koi. Any ideas on what could have caused this or if there’s anything I can do for the sick Koi?...........(ex-sick Koi I have just been informed that it is dead)
<Nothing other than what you have done my young friend. Bob Fenner>

Pond Goldfish Dying Daily
Hi there,
<Greetings>
I hope you can help me.  I have been looking at the info and FAQs on your site for about the past 10 - days during which time I have lost about 30 goldfish -   hoping to find some answers to my dilemma.  (By the way It is a terrific site and has taught me so much - Thank you).  
However, I can't quite find a similar situation to my problem and can't get through anymore reading in fear of there being no more fish left by the time I've covered every FAQ!
Firstly I will tell you I live in Australia.
I have a 2000 litre fibre glass pond in my back garden  established for 2 years 4 months.
I have a Oase Aquarius 4000 E pump with an aerating type of fountain head that I can regulate which takes the pond water to a bio filter and then (by gravity) comes back into the pond by another inlet.  I can control the flow rate of this too.
<I understand>
I have 3 medium and 2 small water lilies in pots I have a dwarf papyrus and a large tall papyrus again in pots and two small pots of water irises.  I took out my huge pot of grass and much of the elodea and parrots feather with the first two deaths as it had spread so thickly and old growth had died off under the water and I wasn't sure it might not be bad for them.
I started off with about 30 goldfish (comets - some with long tail fins, some with short -  plain gold and Shubunkins and two fantails) of varying sizes (mostly under 2 inches as they were the babies which I transferred (without any problems) from my other pond (680 litres) that I have in my front garden when it started to become over crowded.
Out of that 30, 5 fish were between 6 and 8 inches long. About 8 months later I purchased 5 more large goldfish (10 inches plus).  Needless to say they bred and the babies grew (now about 5 to 6 inches long including tales and I had about 58 that I could count - Again I thought it was time to put in yet another pond to move some of these to due to overcrowding).
<Good>
That was until 7 weeks ago. Until then I had only ever lost 1 of my big guys in all that time (dropsy - I brought her back and got her scales down and she lived happily for a further 6 months before she went) and none of the small ones.
Late one afternoon while having a regular check I noticed a 2 inch grey baby just floating on its side with the water lily leaves.  It didn't look as if it had been dead for long as it didn't have any marks on it and it's eyes were fresh and clear.  I took it out immediately thinking it must have just been a weak little fellow.   Next morning I checked again and I noticed my big white girl with her nose parked in the large papyrus plants roots about quarter of the way down.  She didn't come with the others to get food (floating pond sticks) On further inspection we thought she was gone so we pulled her up with the net.  
Again no marks blotches or anything and eyes so clear and fresh - I figured it must just be a heart attack.  None the less I medicated water with Melafix which my local aquarium recommended in case of bacterial infection and did a half water change. (great - we have water restrictions at present but managed to recycle to the garden!)
<Good>
The water for some time has been very murky looking.  We have green algae growing off the walls of the pond and also off the underside of lily leaves and stems etc.  The fish pick at it so I have cut them back a bit on their food.  They kind of demand feed.  They see me and I throw a small handful in - maybe sometimes 3 times a day. The food all goes in about 30 seconds.
The water usually starts off clear in the morning and then as the sun gets warmer or brighter (because the sun is strong even in winter when the weather temperature is less) it starts to cloud up sometimes to the degree where you can't even see a few inches down.  During the winter I got sick of this and turned the pump and filter off  for a month or so (which I have always done periodically over the 2 and a bit years I've had the pond) because I felt that this just contributed to the murkiness by stirring up the water.  There seems to be enough movement and it doesn't go stagnant or get too many mosquitoes or anything.  But it didn't stop the water from clouding up that much.  We only turned the pump back on and started to operate the bio filter again once we found our first two dead fish.
<I see>
Then we were OK for about 4 weeks and it was just after Christmas that I found one of my 5 inch gold baby comets just floating. - Again I couldn't see anything wrong and it looked as though it had just gone - I was shocked - Then a few days later another - same size and type.  in the following days they mostly all started to gape at the surface.  
very listless not interested in food.  Water still murk central.  I did PH test and came in a little high but not out of the range.  About 7.4.
<A good clue>
  I noticed that some of my fish had started to get this sort of mucous covering them and eyes bulging and gasping at surface.  Aquarium told me mucous was because they were stressed and there was a problem! with the water.  One guy there told me to completely empty pond and start again.  So we pushed fish to one end and started to empty pond (again) and took it down to about 8 inches. and scooped out heaps of sludge from bottom -
<Yes... a root cause of your losses here>
(I've got those Dragon fly Odonata things in there which I've never found to cause a problem)
<These can be large enough to predate small fishes>
  but I couldn't empty it completely as I couldn't get all of the fish out.  Also we cleaned out the bio filter as the aquarium people suggested - to start from scratch again.  We refilled with tap water blasting quite a bit in there to create oxygen (as this is what they seemed to lack from looking at their bulging eyes and gasping) and added the appropriate amounts of chorine and chloramine inhibitors to the water.
<Okay>
Next day many fish appeared a bit better.  But some still mucousy and gasping at top.  Two had red streaks in there tails and I continued to treat the pond with MelaFix. (they died)
But  the pond water even murkier and more sort of brown.  I noticed that most of the algae had gone from the walls of the pond too.
<Likely mainly cycling signs...>
Two more fish dead the next day.  And my first baby ever (now 7 inches and fat) - gone.  I couldn't find her in the pond.  It must be dead and trapped under something.   She was very covered in mucous just before she vanished.    I decided to go back to local aquarium and get tests for ammonia nitrate and nitrite and hardness.
<Good>
which they did - only ammonia a little up.  I purchased Zeolite Ammonia Remover bags and  put in the bio filter. Also some water conditioning salt to get the water a little harder (didn't need much).
Over the next few days more fish started floating some had been dead a while and just surfaced by the looks of them and some only freshly gone. Still many of them looked so perfect without marks.  I started to identify the ones that I thought were going to die as they seemed a little disorientated and gaspy at the surface.  So I thought I would transfer them to small Hospital pond I had readied so I could keep a closer eye on them.
NOW THIS IS WEIRD. As I took them out of the pond and put them into the bucket containing water from their own pond to transfer to hospital pond they started to flip and turn upside down and jump out of the water and then lay there - They would be dead within seconds.
<Sounds like something in the way of a residue was in/on the bucket>
  I did this to two slightly sick 5 inch comets that I thought I may be able to save if moved them out of the 'poison pond' quick enough and they were dead with in seconds.  I thought it must be some weird co-incidence and a day later tried it with another fish (small 1 inch long) same thing.  
Jumped all over the place gasping in the water and just died in seconds. Then I tried it again with another but didn't remove it from the big pond with a net.  I scooped it out in a small container without it leaving the water at all.  This survived a little better for about a day then died in the hospital pond. (jumping again.)  It looked like I'd thrown them into a pot of boiling water or that they were being electrocuted.  After scouring your site I thought it may be gas bubble disease and something to do with gas pressures inside and outside of fish -  although I could not find any evidence of little bubbles on them some did have slightly protruding eyes.  And I don't have anything aerating the water from underneath only from the external fountain head!
This morning my big 12 inch red and white girl was floating.  She looked perfect.  Fresh eyes and brightly coloured.  The mucous (which traps the algae particles) that covered her body  yesterday seemed to have left her  and she looked very clear and bright.   Water still murky maybe a slight smell too.
<Something like rotten eggs, or at least a dank, dirt-like smell?>
I can't even see many others in there - I know I have 5 largish ones left 3 of those I haven't seen today.  I can glimpse a couple of red shadows moving around under the water.  
They seem to have gone quite deep.  They sometimes come up for food a bit.  But they seem to 'dart' quite a bit swimming fast and incoherently down in the deep.  Two have got tail rot.  (I am still Melafixing).  So I went back to the aquarium this afternoon and got them to redo there tests again today's (10 days after the last) and they are clear.  NO AMMONIA.
<Be aware that ammonia is quite transient... by the time you take a sample to somewhere it can well have evaporated>
  Everything else normal too except water which could be a little harder.   They are at a loss.  I came home and two more 2 inch babies were floating - one of which I recognize as being one of the fitter and healthier ones two days ago.  I know I'm going to lose my big fantail next (I've had her for 6 years) - she is one of the ones that has fin rot and her eyes are bulging. - I am frightened to take them out of the pond to transfer them to hospital pond now as I think I will kill them due to that darting and freaking out business I mentioned above.   PLEASE HELP.
Thanks -  I know it's a long email but I'm trying to paint the whole picture.  Oh yes the other thing in the last few weeks it has been very hot here.  I have tried to shade the pond a bit with garden umbrellas - I don't know if that's relevant or not. I've seen in FAQs that the heat can have an effect depending on the condition.
Thanks again
Carol
<Thank you for your careful relating, good notes. You appear to have some source of chronic poisoning at play here... most likely the soil and/or what you have used for fertilizing your potted plants... the low pH (it should have been much elevated by daytime driven photosynthesis) is evidence here as well as the order, size of your fish losses, and their timeliness... the move to reduce the sludge was a good one... as was the addition of salt. The Melafix I would hold off on, as this is working against you more than for... stalling biological conversion... A few things going forward... A five hundred gallon/2000 litre system may seem large, but it should not be overstocked (yours was)... particularly during the warming months (Australia for folks in the N. hemisphere) has its seasons switched of course... winter here is summer there... With the warming water you need more biological filtration than the Oase unit can provide... or as a corollary, much less feeding... I would re-pot your aquatic plants... blind potting them per here: http://www.wetwebmedia.com/PondSubWebIndex/Pond%20Sub%20Web.htm
and re-add the floating grasses (Elodea...)... You may be able to discern the cause of the acute poisoning in the bucket you mention... through PolyFilter use (it turns colors per source metals)... or taking it to a lab, college... but I would definitely exclude its use around your ponds... Much to do, relate in turn... there could be an/other source of poisoning here... agricultural, pest likely... am hopeful that by cleaning the pond out (get rid of those Odonatans) and re-potting the plants, either low-stocking or adding/building a bigger filter, you will have renewed success. Bob Fenner>

Concern re stagnant water in Koi pond plumbing
Hi, I am a fifteen year old girl in urgent need of assistance.  Water that had been stagnant in my pump system for many months was accidentally pumped back in the pond today.  Will it kill my Koi and if so is it too late to save them? 
Thanks,
Elena Payami
<Likely not if it did not immediately affect their behavior. If the system is large, the water disrupted/exposed to the air as in a waterfall, filter... there should be little trouble of low oxygen or anaerobic product/s in the small amount of water in your plumbing lines. Bob Fenner>

Fish Pond, or Wishing Well?
>Hi, I have recently built a 1m diameter fish pond and hope to put some fish in it, but my family wants to use it as a wishing well, but would the copper harm the fish?
>>Please, for future reference, we kindly ask that all use proper capitalization so that we do not have to retype queries (we get a LOT every day). Little copper is used in our (U.S.) pennies of today, mostly replaced with zinc if I recollect... But it seems you're from the U.K. and I honestly have NO idea how your coinage is alloyed. In any event, copper is an insecticide/parasiticide, and it used to be that copper pennies were problematic in large numbers (even small numbers/amounts, especially in systems with invertebrates - I worked a shop where someone tried to kill our fishes, as one day we discovered at closing there were pennies in almost all the tanks. Surreptitious, but ill-informed, indeed!). 
I personally would strongly recommend against doing this, but not for the reasons one might initially consider. First, tossing things other than food into such a small pond is only going to startle and frighten the fish. They may bang themselves about being so surprised, not a cool thing to do to an innocent fish. Second, when they become larger, they may try to eat one, which could very well become lodged in their throat, again, not cool. Third, if it became truly habitual, and your Queen's mint/treasury still uses a good amount of copper in her pennies/pence, it could indeed become toxic. All around, not such a good idea in my opinion. Far better to teach your fish that YOU are the ones with food, they will learn to come "beg", much more fun. Marina
>Many thanks - Anna 

Algae/Fish Killer Help
Sir, I picked up your name on ASK.com.  I am having trouble with an outdoor fish pond.  I obviously put in too much Algicide, and killed all of my fish.  Is there any way that I can neutralize the chemical without draining the pond?
<Not practically... most expedient to do a series of massive (tens of percent) water changes here>
I have a 5000 gallon pond, without a drain so I would have to pump it all out into the street.  Any help that you can give me would be greatly appreciated.  Thank You!!
Jan Shepherd
<Mmm, if there is any change in elevation, you may well be able to siphon the water... better from the bottom, along with mulm... Bob Fenner>

Whirling Vortex of Doom, or Fun With Tadpoles? - 06/07/2005
Dear Sirs,
<And Ma'ams!  <grin>  Sabrina with you, today....>
Hi!
<Hello!>
I live in Michigan and have a pond that is approximately  35x75 with depths of 3 inches to an average depth of 5 ft to one section that is 12 ft.
<Wow, very nice.>
Our pond is lined as the water table was too low. We installed this 5 yrs ago. Shortly after we had it filled a snapping turtle was found to be in it carrying with him leeches.
<Eew.  There aren't a great many living things that I truly dislike....  among them are hydra, Aiptasia, most disease-causing organisms, and leeches.  Ugh.>
We got rid of him but the leeches stayed.
<Naturally.  Undoubtedly, they were plotting to get between your toes and latch on....  Evil little creatures....>
We were told to use copper sulfate to get rid of them which they did.
<Sure would.>
My neighbor came down who happens to be a "water environmentalist"
<I'm almost afraid to ask, but what precisely do you mean by "water environmentalist"?  Are we talking a jolly, down-to-earth fish hugger, or someone with OCD who honestly believes that swimming in a river is a heinous crime because you might, god forbid, kill an amoeba?  I mean all that lovingly, of course.  Diversity is, after all, what makes this world a good one to live in.>
and said my husband put too much copper sulfate in the pond and said his kids were never to be in my pond.
<Hmm....  How much CuSO4 did your husband use?  Did your husband disclose the amount to your neighbor?  If so, does your neighbor have any facts or statistics, or a scientific background, to properly understand whether or not there is "too much" CuSO4 currently in the pond?  What, to your neighbor, constitutes "too much"?>
He told me its not safe.
<Well....  To be quite honest, I *do* have to agree with him that CuSO4 is "not safe", to some extent.  CuSO4 is pretty nasty to all invertebrates, and something that I urge aquarium owners to really think about before using it, as it can be adsorbed into the substrate to be leached out at a later time, and cause inverts to sicken and die.  But, again, it would help to know how much CuSO4 was added.>
We still have frogs, water bugs and tad poles living in along w/ a few painted turtles every now and then.
<The water bugs alone make me think there is not, or not much, CuSO4 currently present in the water.  Water bugs, any and all of 'em, are invertebrates, and thus are SIGNIFICANTLY more sensitive to copper than, say, a fish, LET ALONE a person, even a kid.>
I do not remember how much my husband put in but he bought what he needed per what he told the salesman.
<Perhaps you can find out the amount from the salesman?  Perhaps, given the same facts you gave him before (probably dimensions or volume of the pond), he can tell you what he would've sold you?>
My question is, is my pond safe?
<Well, to be precise about it, I have insufficient data to give you an accurate answer.  But from what you've told me so far, given the choice to drink a glass of your pond water or a glass of water from a four-star hotel in Egypt, I'd take your pond water in a heartbeat - provided I was allowed to pull any tadpoles or turtles out of my glass, first.>
My neighbor came over last summer to see what we had done and he made the comment that there was a lot of copper in my water because it was blue.
<Uhh....  *what*??>
I told him that we have not put any copper sulfate in since that first time and that the pond was blue because we put blue dye in it.
<Yeah, oh-kay, to my understanding, there is NO CuSO4 offered for use in aquaria or ponds that will turn your water blue.  I've worked with Copper II Sulfate in chem lab, and the crystals were a very inviting azure hue (one of my favorite shades, in fact!), so maybe that's what has him thinking this?  Either way, my GUESS is that the blue dye you are using is probably Methylene blue, a flavine dye, which in small quantities is essentially harmless to people - I wouldn't want to chug it out of the bottle, as that would probably cause some serious damage to me, but splashing around in a pond with a little bit of m. blue in it wouldn't be disturbing.  But....  I have to ask....  WHY are you using it??  I do recall having seen such a product claiming to prevent algae....  There are other "less blue" options to prevent algae, if you're interested.>
His daughter was over yesterday along with another friend of my daughters and they ended up at the pond trying to catch the tadpoles.
<A very noble quest, at a young age.  I have to admit, I still play with tadpoles, and have several in the tanks I have outside on my porch, thanks to some native very noisy and cute frogs that like to stick to things like suction-cups.>
The little girl said she could not "touch" the water whatsoever
<Sure, she might get wet.  And if she got wet, the world would end.  Or something like that.  Right?>
and that her dad was going to sneak down and check on her.
<Wow, very trusting of him.>
I'm very good friends with these neighbors and don't want that to change but he is really ticking me off saying these things.
<I can understand.  I really don't like when people jump to conclusions without having ANY facts to go off....>
I would like to tell him once and for all that my pond is safe. Can you help me out?
<If you stop adding the dye, once the pond becomes colorless again (as opposed to blue), you can buy test kits to test the copper concentration of the water.  I would hazard a guess that your test results would be zero.  Here are some test kits to look at:  http://www.bigalsonline.com/search/?type=catalog&method=all&collection=sitebuilder%2Fcatalog3-1&keywords1=copper+test .  The dye in the water will skew your test results, especially on the Seachem kit, which is really by far the best of those three.  The other two use different reagents that don't give you blue test results, so you *might* be able to try detecting a change in the color....  this *might* work, but I don't know.  Best to rid yourself of that dye, first, and go with the Seachem kit, in my opinion.>
I forgot to mention that after the copper sulfate was added the first year we had beach sand thrown in over the entire pond surface.
<Umm, how long ago WAS it that you used the copper?  It's starting to sound like we're talking about a matter of YEARS ago?  I see you opened the email with a time frame of five YEARS?  Was it five years ago you added copper?  If so, yeah, realistically, I just don't think that you have a problem with copper at all.  Likely less of a problem than having copper pipes in your house, even.  My best guess is that you're dealing with a father who knows just enough to be afraid but not enough to see reality.  Lack of knowledge is very dangerous stuff....  Utter the words "nuclear energy plant" in a room full of pretty much average folks and you end up with cries of Chernobyl, while hundreds or thousands die per year as a result of coal-fire energy plants to supply those folks' power in their homes....  Same principal.  Just do be patient with your "water environmentalist", and try to gather the cold, hard facts (or wet, sloshy facts, as it were) to prove to him that your pond is not a Whirling Vortex of Doom lying in wait to snatch up his little girl - this is his fear.  If you had a fear, no matter how senseless or unfounded, that something would without a doubt harm your child, you'd do everything to protect her, I'm sure.  Though your neighbor has no reason to, this is what he is doing.  So do be sensitive to him as you try to guide him to a better understanding.>
Signed, Cindy
<Wishing you and your Whirling Vor- I mean, pond- well,  -Sabrina><<Copper is used in most, if not all potable reservoirs in the U.S., elsewhere... It is very safe to swim in, let alone drink in dilution... After being added, it will "fall out of solution" almost entirely w/in a few days. RMF>>

Koi dying with no physical signs 6/29/05
Hi
<Hello there>
I have been searching your site for possible causes for the death of my fish. I have lost one a day for the last seven days. The pond is new (about 6500 litres). I left the pond for a couple of weeks before putting the fish (15 small Koi up to 7") into it. The filter and fountain were running for the entire period since the pond was filled.
I had read quite a few of your responses to other owners with similar problems (fish dying with no outward signs). The fish that have died became loaners, not feeding and began swimming at a very shallow depth and would die within 24 to 48 hours of showing these symptoms. Whilst reading one of your replies about possible deaths caused by poisoning by weed killers/pesticides etc.
<Or the system just not being cycled... the root cause here is almost assuredly environmental>
it suddenly dawned on me that my pond design may actually be poisoning my fish. The pond is part dug and part raised and lined (not a problem). However the top edge of the pond was finished with 6" wide decking timbers. I realized, whilst reading your replies, they were made from tanalised timber (for those who may make the same mistake as me but are unaware of what tanalised timbers are, they are timbers treated with cyanide). I have made a presumption that when it is raining the cyanide is possibly getting into the water (not 100% but I think it is a strong possibility). Of course I immediately went out and took these timbers off my pond and will drain it first thing in the morning.
<Yikes!>
Could you please let me know your views on this? If you think I am right then I hope this information may help others who have made (or might make) a similar oversight to mine!!
Ps. Great site!!!
Regards
Stephen Robbins
<You are correct in that treated lumber can be real trouble... A sample of the water might be taken to a quality assurance or college laboratory for analysis... Perhaps the timber can be sealed with something making it impervious to water... like polyurethane... Or it can be moved, the pond modified such that water that does come in contact does not wash into the basin. I wish you well. Bob Fenner>

Lessons in liner differences... some are toxic to pond life 8/5/05
We are new to the Koi Hobby, and just built our 1st pond in May,  we have had 7 fish since July, but developed a slice our current liner, so we had men come out and put in a new PVC Blue liner,
<Is this a swimming pool product? Some are treated with chemicals that are undesirable for biological systems>
We moved the fish to a large horse tank  for 3 weeks, while we went bigger and deeper with the pond. we went to our first Koi Pond tour, and got new info and designs.
<Ahh! An "eye-opener"... which invariably folks wish they'd done before setting up...>
Needless to say, they finished installing the new liner on Sat, July 30, and we got the filters going,  the water was clear on Tuesday night, and water test are good, so the fish were transferred back to the pond. We came out on Wed night and the small fish were dead,  The large one was still doing ok, swimming around. We took the water in for testing on Wed night, and all the water tests are normal.  I questioned the oxygen,  it is a 1800 gal pond.
But that came within limit, he indicated that bigger fish would have died first if not enough oxygen.
<This is so>
The water filters completely 2 times a hour with the pumps/filters.  Today the large Koi is dead.  The pond people said that
maybe the liner is toxic,
<Yes>
How can we Tell,    the liner people said it is non toxic.  
<Non toxic to what? Swimming humans... you can "do a bioassay" with water taken from the exposed liner, or soak a piece of the liner in water that you know otherwise to be okay... or ask to see the manufacturer's information re this liner... or take the liner to a QA lab...>
We have well water,  have added  nothing except Koi Clay.  He gave us black crystals to put in a hose and put in the outlet water, to capture any toxins.
<...?>
Help!!   My husband is terribly upset as are the children.  If it is the liner, how can we fix it??
<Can either wait, see if time going by, perhaps chemical filtration will remove... plasticizers, anti-mildew/algal material... or remove, or place a non-toxic liner over this in turn...>
   If it is the liner, can it be treated, so we do not have to tear it out,  does it wear off?
<Likely the latter does occur... but how long...? Bob Fenner>
Carolyn

Sick Goldfish Downunder  8/16/05
Hi there,
<Howdy>
I have a 400 litre outside fish pond with around 14 goldfish.
<Yikes... dangerously crowded...>
2 are around 11 years old, (about 9 inches body length) 6 are self sown and range from 7 to 4 years and 6 were bought about 4 years ago.  One of the old ones has had a protruding  right eye for several years and did not appear to be affected by it.
<Happens... resultant likely from a physical trauma...>
More recently the protrusion has increased significantly and the other eye is showing similar symptoms. Now the other old one is showing some eye protrusion. Yesterday whilst the two old one were “basking” in the sunlight I noticed that lumps have erupted around the body of the second ‘old’ one. Looks like cysts but no colour difference. Is there any treatment I can use to fix either or both problems?
<Mmm, just environmental improvement... they need many more gallons of space...>
Since day 1 they have been fed with commercial granular fish food except when we go on vacation when I give them a slow release block.
Occasionally there is an algae problem which I treat with Simazine
<A common ingredient (for our readers) used in commercial ornamental algicides (Princeps powder...)>
and in summer a flocculent. Pond is clear water filtered with a bubbler and with pond weeds.
Can you help?
Thanks
Russell
<Really... what you, they need is a larger, less-crowded world. Though you've had good success with all these fish in a mere hundred gallons or so for years... they're "getting old" (maybe they and I can start a club?), and the vacillating water quality, exposure to the Simazine... is taking its toll... Do consider either "thinning the herd" or building a larger pond. Bob Fenner>

My Koi are dying - please help... algicide?  8/30/05
Hi Fenner,
<Madeline>
Last month my 18" 3 year old female tricolored had what seemed like a seizure.  She was spinning in the pond and all the fish were bumping up against her.  She swam toward the edges and I thought she was trying to spawn.
<The other Koi might have been trying to "help" the sanke>
I put my hands in the water and she swam into them.  I noticed that the top of her head was badly bruised as were the sides and bottom of her.  
<Likely from bumping into things>
I put her in a quick salt dip and then let her swim in and out of my hands while in the pond until she felt better.  (They all take turns laying on my hands if I put my hands in the water, I am very careful not to touch them too much to avoid sandpapering their skin.)
<You are wise here>
  She seemed OK for a week but then died. Last week my 21" 4 year old female yellow Ohgon did the exact same thing but there weren't any fish near her and when she swam into my hands she didn't have a single bruise.
<Frightening>
She did look like she had eggs.  Yesterday morning she seemed perfectly fine but when I came home in the evening she too was dead and was badly bruised - same exact type of bruises.
<!>
I am absolutely heart broken with these losses and fear that my other fish will also pass.  Also I am concerned because I now have only 1 female, 23" and the rest are male.  They have spawned without a single problem for years.  Have you ever heard of this type of problem?  Can you please suggest anything that I can do.  What am I doing wrong?
<I suspect poisoning or something bacterial in origin here... a version of "Ana aki"...>
Here are my pond specifics:  3,500 gallon pond average depth 5' that was built by a pond company.  The filtration is excellent and the waterfall is always on.  I use Algaefix,
<Please see the MSDS re this here: http://householdproducts.nlm.nih.gov/cgi-bin/household/brands?tbl=brands&id=1020010
I would suspend its use>
Kent Pro Clear, MicrobeLift and Dechlor per directions and as needed.  I have a master test kit and the water results are always perfect even the salt level.  Up until a month ago in all my 8years ponding I never had a sick fish.  I give away the fry to keep the population down.  They were always very healthy and the smaller ones only came up 'missing' due to the Herons and Egrets close by.  Two months ago my 23" metallic was dragged out of the pond by a Heron.
<Bold>
It bruised the body of the metallic and then ate part of the dorsal fin and tail.  I stepped outside as my Miniature Pinschers chased the bird away.  I was able to save the metallic and he is now doing fine but is still a little washed out.  The remaining fish move about with energy and look good.  I now have 5 Koi average length 20"-25" and 4 small average length 6"-8".
Thank you in advance for your help,
Madeline
PS  If you feel like responding will I know when you post or do you respond via email as well.  I really could use your help.
<We respond directly to all, post most all. Please read here re Furunculosis: http://www.wetwebmedia.com/PondSubWebIndex/holedispd.htm
Acute cases often manifest themselves as your fish's symptoms... I would have the dead fish necropsied (see your veterinarian re who in the area has expertise), cultured for Aeromonas... Adding salt may well be efficacious in this circumstance. Bob Fenner>

Pond in serious trouble... poisoned at least by Algicide  8/27/05
I have been going to my local pond supply store and trying to get help on   this problem.  I would love to hear your advice.  First the pond  started getting a lot of green slimy algae.  The store said to add barley  so I did.  No help.  Then after a week or so they suggested adding  more plants.  So I did no help.  Then the store suggested algae fix,  and a white powder that you put on top of the water after removing all of the  plants and letting this powder sit with the filters off for 20 minutes.   This did nothing.  Now the pond smells really bad the fish are dying and I  still have both green and brown algae.  
You can't walk in the pond as the  bottom is very slippery.  Do you have any suggestions?  
<... yes... study... What is it about your pond for instance, that inspires such algal profusion? What is your water quality... particularly nutrient levels like nitrate and phosphate? Do you have an adequate biological filter? Circulation? The Algicide you've used is toxic, and is killing your livestock... I would start a series of large water changes to dilute this, or move your livestock out entirely...>
I have lost 2  3.5 to 4" gold fish and 3 or 4 small babies.  I don't see any sign of  disease,
<... environmental disease, poisoning...>
but I have noticed that all of my fish have
stopped eating.  They  also seem to be very lethargic.  Please send any help that you can.   Thanks  
Sissy
<Start by reading here: http://www.wetwebmedia.com/PondSubWebIndex/pdalgcontrol.htm
and the linked files above. Bob Fenner>