Hemorrhage (In My Pond) - Just Poor Water Quality? - 08/19/2004
Last Saturday I added some common goldfish and 4 Koi (the Koi are only about 4" long)  to my backyard pond/waterfall.  The water has been circulating almost continually since the addition of the fish to provide oxygen and help prevent the growth of algae.  
<Almost continually?  Not constant?>
I have not tested, at this time, the condition of the water to make sure all the levels are within fish tolerance.  This morning I ended up removing a dead goldfish that appears to have had some hemorrhaging around the eyes and scales, nothing around the gills however.
<I would *immediately* test ammonia, nitrite, and nitrate, also pH (if you can, compare your pond's pH with that of the store where you got them).>
Prior to the fish dying, I noticed that his movement in the pond seemed lethargic and he was having some difficulty maintaining his equilibrium.  I recently went and checked the pond again and am seeing yet another goldfish with similar symptoms as the first.  I checked for any signs of hemorrhaging and see small red spots under both eyes but nothing like the first one.  Any suggestions?
<First and foremost, with so much life added at once - and you only say 'some' common goldfish, I assume this is a higher number than the 4 Koi - I would not be at all surprised if ammonia and nitrite are, or at least have been, highly toxic.  Please test these values - without knowing them, there's no further I can recommend.  If ammonia or nitrite are not *zero*, you'll have to do some hefty water changes (a PITA in a pond - yikes!) to bring them back down.  Please do keep us updated, and we'll try to be of more service, once a problem/solution can be had.  Wishing you well,  -Sabrina>

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>