Mysterious Death
Hello,
<Hi.>
I’m thoroughly confused.
<Me too, a great deal of the time.  This condition can often be easily combated with books and other resources concerning the topic(s) which confuse you.  Oh.  Wait.  There's more to this, isn't there?  Something fishy, perhaps?>
I have just found a dead goldfish floating in my pond.  
<Sorry to hear that.>
The pond is about 12ftx20ftx3ft deep (at it’s deepest point) and has been established for about 5 years (2 comets, 4 goldfish, 5 Rudd
<I had to look "Rudd" up; I've never heard this common name, nor seen pictures of this Eurasian cyprinid.  Cool looking fish.>
and numerous sticklebacks).
<Sounds good, so far.>
The fish is about 4 years old and is approx 6 inches long and appears in perfect health – all the fins are intact and the colour is fine –
<Sounds excellent, minus the bit about being dead.>
I thought it was just resting but it was on a slightly strange angle (maybe dead for an hour or so at most I think) and the fish is a good weight and size and has no outward signs of disease or parasites or damage etc. The temperature is probably btwn 2-6 degrees Celsius and there has been no ice on the pond for a few weeks now (I'm in the UK) It is the first fish I have lost from the pond (apart from the odd stickleback every few months at worst)
<First thing to check is water parameters - find out where you're sitting for pH, ammonia, nitrite, and nitrate.  It would also be a good idea to check your oxygen level.  Another point to consider, are you feeding the fish? At these cold temperatures, the fish cannot benefit from the food, and it really only contributes to waste buildup, which can cause ammonia, nitrite, and nitrate to rise to perhaps toxic levels.>
I am a relatively experienced fishkeeper (6 years tropical/coldwater) and I just don’t get it?  Do you have any idea what could have caused this?
<In all honesty, this may be a completely unsolvable mystery.  It is entirely possible that the animal died of something unexpected and sudden, just as other animals and people sometimes do.  Dissection may shed some light on what did him in, but other than that....  Test your parameters, rectify if necessary, and don't lose too much sleep over it, at least.  Everything sounds good otherwise, really.>
Many thanks,  Paul Newman
<Any relation to.... no.  No, I am *not* going to ask that.  I get enough "teenage witch" comments, I can understand where you'd go nuts if I asked you that, so I'll refrain.  Wishing you and your pond well,  -Sabrina, neither teenage, nor a witch>

It's Not Easy, Bein' Green....  06/20/2004
Hi,
<Hello.>
I have a large outdoor pond (1400 gal).  Two of my goldfish developed a green fungus on the skin on both sides of their bodies.
<Wow, now *that's* something wholly unfamiliar to me.>
One died, the other just developed the same symptom.  Do you have any idea what it is?  
<'Fraid not....  I'll be hitting the books, though, and see if I can find anything.  Meanwhile, if you could please respond with ammonia, nitrite, nitrate, and pH readings, that may be of help.  Also, any other symptoms the fish may exhibit - lethargy, clamping of fins, any marks or discoloration (besides the green), perhaps also describe the green fungus in a bit more detail (fluffy, stringy, grainy, bright green, dark green....)>
How to cure it?
<Sorry I'm not of the greatest help, at the moment.  Please do respond, though, and know that I'm trying to find any info on the situation as you describe.>
Thanks for the help.
<Hoping to be of better service,  -Sabrina> <<Likely env. at base... RMF>>

Koi with sudden Curvature Of The Spine?
Hello, thank you for running this awesome site.  One of my Koi, 11 months old, about 7 inches long (approx 1 inch less than others his age) and while they appear to be maybe overweight, is in good shape but not as heavy.  He/she is an orange and white Kohaku and I have often thought in the last month or more that it had developed a slight kink where the body meets the tail itself.
<Not good... thank you for the useful info. above... such twisting/kinking is likely genetic here... though can be infectious (e.g. Myxosoma), nutritional in origin>
All Koi are growing like crazy, eating out of my hand, surfacing to allow me to pet their heads, except this one?
Now today I noticed that it is bending its back third of its body most of the time making it swim crooked and unbalanced.  In fact with its body straight while motionless, it lists to one side and stops the listing by suddenly kinking the last third of its body (approx. from the rectum back?)
It seems quite bad?  So my questions are:  If it was normal at birth, why is it now developing a Curvature of the Spine or whatever is happening?  I switched to a higher protein food in the last month or two.  They are fed some Wardley's Pellets and Wardley's Tubifex Worms, some Nutrafin Spirulina Algae Flake Food and some Hikari Gold Pellets.  Averaging out the protein comes to 40%.
<Mmm... I would offer "regular" Koi food prep. (pelleted) foods... better nutrition and MUCH less expensive.>
Water temperature is consistent at 68.5 degrees Fahrenheit.  I vacuum off 20% of the water daily, removing all traces of debris on bottom of tank.
<This much protein is "okay" at this temperature, but it would be better for your Koi to eat less protein percentage... like twenty percent maximum, and grow more slowly... will live longer, healthier lives...>
My well water straight from the well has a pH of 7.0  High range pH of 7.4  Nitrate 10 and Ammonia between 0 and -.25 as so hard to decide on the color graph with my Master Test Kit on that Ammonia?  Well water is tested safe for Human Consumption every year.
<Then it is fine, I assure you>
Tank is consistent at pH 7.6  High Range pH at approx 8  Nitrite is always 0  Nitrate around 80+  And that Ammonia comes in around -.25??? Just don't know, MAYBE it is 0 but the color test strip makes me suspect from yellow (0) and kind of a yellow/lime colored (.25)???
<A good idea to store, aerate new water ahead of use... like in a covered plastic trash can, for a week>
Bio filter is cleaned every 14 days.  Foams, pads and carbon is cleaned, bio stars and rings are not flushed with tank water more than every 2nd or third cleaning?
<Ah, you've been studying!>
Tank is a 200 gallon galvanized aluminum stock tank.
<Mmm, hope it's "old"... the galvanization, aluminum can be toxic>
Also Aquarium salt is kept at  less than 1/2 recommended amount for freshwater aquariums.  4 growing Koi and 2 tiny Comet Goldfish.
Water is added back each day after vacuuming as close to 68.5 degrees as possible, rarely out more than .5 degrees.
Any chance you can explain to me what is happening with this Kohaku?  I am thinking it might just be Genetic but certainly don't want it to start happening with my other 3 babies who are more excellent quality.  Thank you kindly, Gayle
<Ahh, we concur re the cause here. I would just enjoy this specimen... it may survive for years... Not a contagion at play here. Bob Fenner>