Hi,

I have a 15,000 gal pond with Shubunkin and Comets in it. I live in
New Hampshire, and the ice has finally melted back here. Water temp is
getting up to around 50, so Spring is in the air and the fish are on
the move.

Last Fall, I had a couple fish die unexpectedly. None of them seemed
to exhibit any problems until I found them dead, and one was a 6 year
old Shubunkin. Even after they died, they looked perfectly fine--no
fin damage, no visible sores, nothing.

At the time, I went into a panic and checked the water (it was fine),
and changed about 30% of the water "just in case." Unfortunately, due
to my water change, the salt I had added was basically rinsed out. No
other fish died, and winter set in.

Actually, to say no other fish died isn't entirely accurate. In May, I
added 14 mosquito fish to the pond on the advice that they were fine
for this zone. By the end of summer, those 14 had become about 1,000.
Seriously. They multiplied like crazy, and typically had 13 babies at
a time. I think they ate the goldfish babies because I didn't see any
more after the mosquito fish came. I had planned on having about 35
mosquito fish, but clearly they had other ideas. Well, as soon as the
water temp dropped into the 40s, all the mosquito fish started dying.
It now appears that they all died off. Since this happened at the same
time as the fish I just mentioned, I first thought there was something
horribly wrong with the water. But, since the water chemistry checked
out ok, I figured that the little guys died of the cold and the big
ones were just a coincidence.

So, now the fish are active again. A week and a half ago, I noticed a
Comet lying on its side. When I went to scoop it out, it swam away. I
had thought it was dead so I figured it was *almost* dead and swam
away to die. A few days later I saw it somewhere else, again on its
side. A few days later it was somewhere else. Every time I went to
net it, it swam away. Since it hadn't died on its own, I decided to
try to save it. For the record, over the years I've tried to "save"
probably 8-10 fish that were pretty far gone, and out of those 8
exactly 0 have survived. Call me an optimist but I keep thinking I'll
break that streak.

Anyway, I read up on the fish in my handy dandy "Koi Health and
Disease" book by Erik Johnson (most of it applies to goldfish as
well), and it sounded like the fish was suffering from gill disease,
probably due to flukes or something like that. I gave the fish a salt
dip in salted pond water, and then put it in a 5 gallon bucket of
unsalted pond water with aeration to observe until the next dip. The
book recommends giving the fish antibiotics, which I'd love to do, but
this fish wasn't eating and my local Petco doesn't sell syringes and
antibiotics. So, instead I put some Jungle Pond parasite killer in the
water and hoped the fish improved. After about16 hours, it was dead.
It appeared to have bled out since blood had seeped into all of its
fins.

Today, I noticed another fish on its side. This was another Comet and
again I figured the fish was dead until it started trying to get out
of the net. So, thinking that it's probably got the same problem as
the last fish, I gave it a salt bath like the last one and then put it
in a 10 gallon aquarium of pond water. I wasn't sure if the bucket was
fish safe, being that it was just a Home Depot orange bucket, and
since the last fish died so quickly there, I thought I'd avoid that
variable. I also decided to bring the temp of the water up so that the
fish's immune system would kick in. So I brought it up (slowly) to
about 60 or so with an aquarium heater. I also went to Petco and got
some Tetracycline to put in the water, since I'm convinced these guys
need some kind of antibiotics. And, again I put the Jungle Pond
parasite killer in the water. Since the fish was in a glass aquarium
this time, I could observe it better. Again, it looked completely
healthy except for its behavior. I *believe* I saw some very very tiny
thread-like things by the side scales of the fish. I can't be sure
though, it could have just been dust or something like that. Anyway,
after going from lying on its side to head-down-tail-up to head-up
just below the surface, it coughed up some blood and died. My record
of saving fish stands. Before I put anything into the water at all,
the fish had already gone to head-down-tail-up mode. It would still
swim once in a while, but it kept going back to that position. So, the
additives I put in the water didn't cause that behavior.

After this fish died, I pressed the gill covers open enough to see the
gills, and they looked (in my mind) completely healthy. They were
uniformly red and not blotchy--kind of like really lean steak if that
makes sense. One of them was really clamped shut, and I had noticed
that there wasn't much gill activity going on while the fish was
alive. I can't tell if this fish bled out in the same way as the last
because it's fins were orange, and I just can't tell if there's blood
in them or not. However, it definitely coughed up some blood.

I'm now expecting to lose more fish, whether I try to save them or
not. There's clearly something going on in the pond. After the ice
cleared and before the first fish I tried to save, I pulled out
another dead fish that was pretty decomposed. I'm not sure when that
one died but I'd guess it was a month or more ago.

What's confusing me is that the water continues to test fine for
things like PH, nitrates, nitrites, chlorine and ammonia and the fish
don't show any damage. They simply start lying on their sides and then
they eventually die. I suspect some kind of organism is in the water,
and for whatever reason I kind of latched on to the idea that there
are flukes in it, although I don't have a microscope to check for that
specifically. This is a large pond, but there are a lot of fish in it.
It didn't start that way, but the fish have been happy and populated
the pond. There's probably close to 80 or 100, ranging from 4" to 9"
tip to tail. It sounds like a lot of fish, but in 15,000 gallons with
6' deep for most of the pond, it's not crowded. I have an oversized
bead filter on the pond because of the fish load, although it hasn't
been running since the Fall. The fish that died in the Fall died while
it was still running.

I'm wondering what I should do to fix the problem. Actually, reading
this, I'm thinking I should get a microscope first and see if I can
narrow down the culprit. I do have some Trapdoor snails in the pond,
or at least I did last Fall. I suspect that they're down at the bottom
right now since I'm not seeing them and that's where I'd go if I were
a snail. The majority of parasite remedies kill off snails, and if I
have to do that, fine, but I didn't want to go that route until I knew
more. I'm leery of putting a bunch of chemicals in the water.

One pond skimmer ran all winter because I had tadpoles, frogs and at
one time mosquito fish in the upper stream. Keeping the waterfall
running was the easiest way to keep that from freezing solid since
it's only about a foot deep. This seems to have worked very well and
I've already seen tadpoles swimming about. The skimmer just feeds the
waterfall and I don't believe it changed the water temp dramatically
since it pulls from the top foot of water and returns via the
waterfall. The pond is over 6 feet deep everywhere except for a shelf
that runs around the edge. It has a bottom drain which goes to a bead
filter and UV light setup in my basement. That returns to the pond
through the waterfall as well, and that system has been off for the
winter. Only the one skimmer has been running. A second skimmer has
also been off.

Anyway, sorry for such a long post. I'm just so completely tired of
seeing these fish dying, I'm tired of thinking I can "save" them and
I'm tired of having them die all the quicker once I get involved. I
did buy some Fin-Quel last year for fish that clearly need to be
euthanized, but I didn't put these last two in that category. At least
not until I "helped" them.

If anyone can give me advice on diagnosing and treating the pond
problem as well as advice on better treatment of sick fish, I'd really
appreciate it. This is my second pond (the other was about 3200
gallons). This pond is two years old and aside from the mosquito fish,
I haven't added any fish to it since it was started. I've been ponding
for 7 years now, and most of the time I really enjoy it. Oh, by the
way, all the other fish are looking completely normal, are very
active, and are already bugging me for food. I have no clue which ones
will be the next to drop.

Thanks,

Dave

I read your post in full and my heart goes out to you.....nothing more
heartbreaking than unexplained deaths....I hope that someone will
respond to you soon with some good advice as I'm sure will happen
knowing the folks on this group......sadly I'm a newbie to ponds so
can't really help other than to offer suggestions that you have already
tried :-(

Gill

Hi Dave,

Not to worry, we have some serious experts in the group.
I read thru your post and just wanted to let you know that
I think they can help you when they check in.

I do know they like the exact readings of any tests you
do so you might be able to run some tests and post those
results for them.

k :-) (*not* an expert, I just hang out with one....)

Thanks, I'm open to any advice or suggestions.

I forgot to mention that I did have (and still do have) aeration in
the pond for the winter. Whenever I shut down the bead filter for the
winter, I put air stones in the pond to keep two holes open for
gasses. They keep two 1.5' holes open in the ice throughout the
winter. I put one set of air stones near a more shallow planting area
where frogs tend to hang out, and then dropped another down near where
the fish overwinter at the bottom. (There's a big boulder down there
resting two smaller stones, making a cave.) The aeration is still
running--I haven't started up the bead filter yet and that's when I
usually pull out the airstones. I want to do some clean up before I
start up the bead filter but I hope to get to it soon.

The other thing is that my estimate of 100 fish is probably a bit
high. I'd say there are definitely 70 and could be as many as 100, but
that's probably a stretch. They don't stand still for a head count so
I'm not sure. The average fish size is probably 5" + tail size, and
some of the tails are quite long. The oldest fish are more like 8-9" +
tail but there are probably around 6 of those.

I looked today and I did notice one fish with some lumps on its side
and one on its head. I'm not sure if that's related or not, since all
of the fish that have died didn't have any visible ailments. This one
didn't come close enough for me to net it for a closer exam. (Smart
fish.)

Thanks for any advice. If there are any questions I can answer, please
ask.

Dave

In article
,
kathy wrote:

Hi Dave,

Not to worry, we have some serious experts in the group.
I read thru your post and just wanted to let you know that
I think they can help you when they check in.

I do know they like the exact readings of any tests you
do so you might be able to run some tests and post those
results for them.

k :-) (*not* an expert, I just hang out with one....)

Can we be informative, but not always serious?

--
To reply by email, remove the word "space"

In k's world, anyone who understands chemistry
and fishy diseases is serious. I understand amphibians
and insects and pond pests and slimy things therefore
I am amphibious? entomologist? slimologist? Anyone
want to talk leeches? ;-)

I sent an email to jan, she's had a long day but should
check in soon.

k :-)

"Pond Addict" wrote in message
...
Hi,

I have a 15,000 gal pond with Shubunkin and Comets in it. I live in
New Hampshire, and the ice has finally melted back here. Water temp is
getting up to around 50, so Spring is in the air and the fish are on
the move.

brevity snips

What is the PH of your pond water and is there a lot of mulm and crud on the
bottom? Did you do the partial water changes on this pond on a regular
basis all last summer and fall?
--

RM....
Frugal ponding since 1995.
rec.ponder since late 1996.
Zone 6. Middle TN USA
~~~~ }((((* ~~~ }{{{{(ö

On Tue, 1 Apr 2008 09:40:27 EDT, Pond Addict
wrote:

If anyone can give me advice on diagnosing and treating the pond
problem as well as advice on better treatment of sick fish, I'd really
appreciate it. This is my second pond (the other was about 3200
gallons). This pond is two years old and aside from the mosquito fish,
I haven't added any fish to it since it was started. I've been ponding
for 7 years now, and most of the time I really enjoy it. Oh, by the
way, all the other fish are looking completely normal, are very
active, and are already bugging me for food. I have no clue which ones
will be the next to drop.

Sorry to hear about your distress over your fish. I wish you well and
believe Ingrid's site has the best goldfish information on the web.

http://weloveteaching.com/puregold/

I have cheap fish and toss the dead one's, try to improve the water
quality for the rest and press on.
--
Hal Middle Georgia, Zone 8
http://tinyurl.com/2fxzcb

On Tue, 1 Apr 2008 22:08:56 EDT, Pond Addict
wrote:

Thanks, I'm open to any advice or suggestions.

Dave

Hi Dave,

There is a med that will kill flukes in the pond, unfortunately in a pond
of your size it would cost $200+. The one nice thing is, one treatment
usually does it, and it is benign to filters, and other aquatic critters.
It just kills flukes. If you're interested I'll look up the name.

Kathy is right though, we'd really like to know what the measurements were
on your test kits. What brand of kit, how old? Paper strips or drops?

Goldfish are not long lived, like their koi cousins can be.

As far as trying to save one, starting with the salt dip was good, but the
other meds just add insult to injury. It would have been better, imho,
after the dip to hold the salt at 0.3% and keep the water pristine and just
wait.

For fish that are common or far gone, fish them out and Finquel them. ~ jan
------------
Zone 7a, SE Washington State
Ponds: www.jjspond.us

Call Jo Ann Burke, the Goldfish Guru. She is an expert in fish diseases.
251-649-4790. She can sort out what the problem is.

Die off in spring is not uncommon. Much has to do with accumulated gases from
decomposition in the pond with an ice cover and the lack of oxygen, especially if the
largest fish are in the worst shape. If you dont have a microscope, do get one, all
you need is 100x to see most of the parasites. Go here for her diagnostic
techniques.
http://weloveteaching.com/puregold/d...c%20techniques

I had two koi die with nothing external, no parasites, and when I did the necropsy I
found infected eggs. Since I dropped in a 500 watt heater, put up plastic over the
pond I get no ice on the pond, the koi eat all winter long and in spring they are
feisty and healthy. I have a "closed pond", that is, no new fish come into my pond
and the pond is netted so no birds or etc. crap or introduce disease into my pond.
Ingrid

On Tue, 1 Apr 2008 09:40:27 EDT, Pond Addict wrote:
I have a 15,000 gal pond with Shubunkin and Comets in it. I live in
New Hampshire, and the ice has finally melted back here. Water temp is
getting up to around 50, so Spring is in the air and the fish are on
the move.

Last Fall, I had a couple fish die unexpectedly. None of them seemed
to exhibit any problems until I found them dead, and one was a 6 year
old Shubunkin. Even after they died, they looked perfectly fine--no
fin damage, no visible sores, nothing.

At the time, I went into a panic and checked the water (it was fine),
and changed about 30% of the water "just in case." Unfortunately, due
to my water change, the salt I had added was basically rinsed out. No
other fish died, and winter set in.

Actually, to say no other fish died isn't entirely accurate. In May, I
added 14 mosquito fish to the pond on the advice that they were fine
for this zone. By the end of summer, those 14 had become about 1,000.
Seriously. They multiplied like crazy, and typically had 13 babies at
a time. I think they ate the goldfish babies because I didn't see any
more after the mosquito fish came. I had planned on having about 35
mosquito fish, but clearly they had other ideas. Well, as soon as the
water temp dropped into the 40s, all the mosquito fish started dying.
It now appears that they all died off. Since this happened at the same
time as the fish I just mentioned, I first thought there was something
horribly wrong with the water. But, since the water chemistry checked
out ok, I figured that the little guys died of the cold and the big
ones were just a coincidence.

So, now the fish are active again. A week and a half ago, I noticed a
Comet lying on its side. When I went to scoop it out, it swam away. I
had thought it was dead so I figured it was *almost* dead and swam
away to die. A few days later I saw it somewhere else, again on its
side. A few days later it was somewhere else. Every time I went to
net it, it swam away. Since it hadn't died on its own, I decided to
try to save it. For the record, over the years I've tried to "save"
probably 8-10 fish that were pretty far gone, and out of those 8
exactly 0 have survived. Call me an optimist but I keep thinking I'll
break that streak.

Anyway, I read up on the fish in my handy dandy "Koi Health and
Disease" book by Erik Johnson (most of it applies to goldfish as
well), and it sounded like the fish was suffering from gill disease,
probably due to flukes or something like that. I gave the fish a salt
dip in salted pond water, and then put it in a 5 gallon bucket of
unsalted pond water with aeration to observe until the next dip. The
book recommends giving the fish antibiotics, which I'd love to do, but
this fish wasn't eating and my local Petco doesn't sell syringes and
antibiotics. So, instead I put some Jungle Pond parasite killer in the
water and hoped the fish improved. After about16 hours, it was dead.
It appeared to have bled out since blood had seeped into all of its
fins.

Today, I noticed another fish on its side. This was another Comet and
again I figured the fish was dead until it started trying to get out
of the net. So, thinking that it's probably got the same problem as
the last fish, I gave it a salt bath like the last one and then put it
in a 10 gallon aquarium of pond water. I wasn't sure if the bucket was
fish safe, being that it was just a Home Depot orange bucket, and
since the last fish died so quickly there, I thought I'd avoid that
variable. I also decided to bring the temp of the water up so that the
fish's immune system would kick in. So I brought it up (slowly) to
about 60 or so with an aquarium heater. I also went to Petco and got
some Tetracycline to put in the water, since I'm convinced these guys
need some kind of antibiotics. And, again I put the Jungle Pond
parasite killer in the water. Since the fish was in a glass aquarium
this time, I could observe it better. Again, it looked completely
healthy except for its behavior. I *believe* I saw some very very tiny
thread-like things by the side scales of the fish. I can't be sure
though, it could have just been dust or something like that. Anyway,
after going from lying on its side to head-down-tail-up to head-up
just below the surface, it coughed up some blood and died. My record
of saving fish stands. Before I put anything into the water at all,
the fish had already gone to head-down-tail-up mode. It would still
swim once in a while, but it kept going back to that position. So, the
additives I put in the water didn't cause that behavior.

After this fish died, I pressed the gill covers open enough to see the
gills, and they looked (in my mind) completely healthy. They were
uniformly red and not blotchy--kind of like really lean steak if that
makes sense. One of them was really clamped shut, and I had noticed
that there wasn't much gill activity going on while the fish was
alive. I can't tell if this fish bled out in the same way as the last
because it's fins were orange, and I just can't tell if there's blood
in them or not. However, it definitely coughed up some blood.

I'm now expecting to lose more fish, whether I try to save them or
not. There's clearly something going on in the pond. After the ice
cleared and before the first fish I tried to save, I pulled out
another dead fish that was pretty decomposed. I'm not sure when that
one died but I'd guess it was a month or more ago.

What's confusing me is that the water continues to test fine for
things like PH, nitrates, nitrites, chlorine and ammonia and the fish
don't show any damage. They simply start lying on their sides and then
they eventually die. I suspect some kind of organism is in the water,
and for whatever reason I kind of latched on to the idea that there
are flukes in it, although I don't have a microscope to check for that
specifically. This is a large pond, but there are a lot of fish in it.
It didn't start that way, but the fish have been happy and populated
the pond. There's probably close to 80 or 100, ranging from 4" to 9"
tip to tail. It sounds like a lot of fish, but in 15,000 gallons with
6' deep for most of the pond, it's not crowded. I have an oversized
bead filter on the pond because of the fish load, although it hasn't
been running since the Fall. The fish that died in the Fall died while
it was still running.

I'm wondering what I should do to fix the problem. Actually, reading
this, I'm thinking I should get a microscope first and see if I can
narrow down the culprit. I do have some Trapdoor snails in the pond,
or at least I did last Fall. I suspect that they're down at the bottom
right now since I'm not seeing them and that's where I'd go if I were
a snail. The majority of parasite remedies kill off snails, and if I
have to do that, fine, but I didn't want to go that route until I knew
more. I'm leery of putting a bunch of chemicals in the water.

One pond skimmer ran all winter because I had tadpoles, frogs and at
one time mosquito fish in the upper stream. Keeping the waterfall
running was the easiest way to keep that from freezing solid since
it's only about a foot deep. This seems to have worked very well and
I've already seen tadpoles swimming about. The skimmer just feeds the
waterfall and I don't believe it changed the water temp dramatically
since it pulls from the top foot of water and returns via the
waterfall. The pond is over 6 feet deep everywhere except for a shelf
that runs around the edge. It has a bottom drain which goes to a bead
filter and UV light setup in my basement. That returns to the pond
through the waterfall as well, and that system has been off for the
winter. Only the one skimmer has been running. A second skimmer has
also been off.

Anyway, sorry for such a long post. I'm just so completely tired of
seeing these fish dying, I'm tired of thinking I can "save" them and
I'm tired of having them die all the quicker once I get involved. I
did buy some Fin-Quel last year for fish that clearly need to be
euthanized, but I didn't put these last two in that category. At least
not until I "helped" them.

If anyone can give me advice on diagnosing and treating the pond
problem as well as advice on better treatment of sick fish, I'd really
appreciate it. This is my second pond (the other was about 3200
gallons). This pond is two years old and aside from the mosquito fish,
I haven't added any fish to it since it was started. I've been ponding
for 7 years now, and most of the time I really enjoy it. Oh, by the
way, all the other fish are looking completely normal, are very
active, and are already bugging me for food. I have no clue which ones
will be the next to drop.

Thanks,

Dave

On Wed, 2 Apr 2008 09:59:19 EDT, ~ jan wrote:
There is a med that will kill flukes in the pond, unfortunately in a pond
of your size it would cost $200+.
.... PP works fine, doesnt really kill the fish and works in cold temps.

As far as trying to save one, starting with the salt dip was good, but the
other meds just add insult to injury. It would have been better, imho,
after the dip to hold the salt at 0.3% and keep the water pristine and just
wait. For fish that are common or far gone, fish them out and Finquel them. ~ jan

.... the 3% salt dip is done if the slime coat is thick, otherwise, a peroxide dip is
easy and gentle on individual fish and it kills dacs as well as gyros. doesnt do
anything to other kinds of parasite tho.
http://weloveteaching.com/puregold/d...m#peroxide_dip
Ingrid

Ok, I re-ran tests on the pond with brand new test kits, just to make
sure I had those results correct.

Aquarium Pharmaceuticals (API) results:
Nitrate - 0%
Nitrite - 0%
PH - 7.7 - 7.8
KH - 5° (89.5 ppm)
GH - 6° (107.4 ppm)

Red Sea test kit results:
Ammonia - 0%

Pond Care test kit results:
Salt 0.00% - 0.02% (Holding off on the salt in case I'm going to put
meds in the pond and then water change.)

I didn't test for Chlorine this time. The water comes from a well, so
there's no chlorine there. No water has been added since Fall, except
from rain/snow.

I did water changes in the Spring, Summer, and Fall. They weren't
regular in the sense of "every 3 weeks" but they were relatively
frequent. There was a big water change in Fall over a few days (so big
that it took my salt from 2% to 0%), when I was concerned about
something bad in the water. I didn't get salt back in it again after
that. : (

Throughout the winter I added Microbe-lift bacteria (monthly liquid
and packet autum/winter care).

I'm going to order a microscope, since that really seems like a
necessity.

Is "PP" PraziPro? I was looking at that because I saw that
Praziquantel was a recommended treatment for flukes, if that's even
what I have. I couldn't find any information on how Praziquantel
affects other wildlife. Will it cause problems for the snails,
tadpoles, frogs, ducks or my cat or dog that visit?

The bottom of the pond has some sediment in it, but it's not what I
would call excessive. It's mostly dead algae and such that's being
broken down in the lowest part of the pond near the bottom drain.
There's also a general fuzz coat around the pond that I'd consider
normal. In case it's relevant, the pond was created by excavating,
putting down a liner, concreting over that, sealing that with a fish
safe coat and landscaping with boulders, etc. It was built in Spring/
Summer of 2006 and there has never been any significant fish loss.
There were mainly "mechanical losses" due to a drain cover I had to
rework. There are skimmers on the left and right of the pond which
feed a waterfall, and the bottom drain goes to a bead filter, a UV
light and back to the waterfall as well. Currently only one skimmer is
active. I actively clean up leaves,etc. that are by the water's edge.

The fish I tried to save were not slimy when I captured them, although
I noticed that one of them had become very slimy by the time it died.
I probably caused a lot of stress with all my good intentions...

Thanks for helping,

Dave

On Wed, 2 Apr 2008 11:20:09 EDT, wrote:

I had two koi die with nothing external, no parasites, and when I did the necropsy I
found infected eggs. Since I dropped in a 500 watt heater, put up plastic over the
pond I get no ice on the pond, the koi eat all winter long and in spring they are
feisty and healthy. I have a "closed pond", that is, no new fish come into my pond
and the pond is netted so no birds or etc. crap or introduce disease into my pond.
Ingrid

At one of the seminars I attended it was mentioned that down south they
still fast their koi in winter for a month, so unspawned eggs will be
reabsorbed. So you might want to hold off on some of that winter chow. ;-)
~ jan
------------
Zone 7a, SE Washington State
Ponds: www.jjspond.us

On Wed, 2 Apr 2008 11:20:21 EDT, wrote:

On Wed, 2 Apr 2008 09:59:19 EDT, ~ jan wrote:
There is a med that will kill flukes in the pond, unfortunately in a pond
of your size it would cost $200+.
... PP works fine, doesnt really kill the fish and works in cold temps.

True, but in unskilled hands, I don't recommended it, and it can be hard to
find in some places. ~ jan
------------
Zone 7a, SE Washington State
Ponds: www.jjspond.us

On Wed, 2 Apr 2008 18:44:47 EDT, Pond Addict
m wrote:

Aquarium Pharmaceuticals (API) results:
Nitrate - 0%
Nitrite - 0%
PH - 7.7 - 7.8
KH - 5° (89.5 ppm)
GH - 6° (107.4 ppm)
Red Sea test kit results:
Ammonia - 0%

Those look just fine.

Pond Care test kit results:
Salt 0.00% - 0.02% (Holding off on the salt in case I'm going to put
meds in the pond and then water change.)

I'd bring the salt up to 0.1% (most meds can be used with this amount of
salt).

Is "PP" PraziPro?

Prazi was the expensive stuff I recommended, but now that you're ordering
a
microscope, you might as well scope them first.

PP is Potassium Permanganate.

Will it cause problems for the snails,
tadpoles, frogs, ducks or my cat or dog that visit?

No, fairly safe stuff. Well... it may clean the gut of the above animals
if
they've got flukes. ;-)

There's also a general fuzz coat around the pond that I'd consider
normal. In case it's relevant, the pond was created by excavating,
putting down a liner, concreting over that, sealing that with a fish
safe coat and landscaping with boulders, etc. It was built in Spring/
Summer of 2006 and there has never been any significant fish loss.
There were mainly "mechanical losses" due to a drain cover I had to
rework. There are skimmers on the left and right of the pond which
feed a waterfall, and the bottom drain goes to a bead filter, a UV
light and back to the waterfall as well. Currently only one skimmer is
active. I actively clean up leaves,etc. that are by the water's edge.

Sounds to me like you did some serious research on how to build a pond th
e
right way, and didn't skimp.

Thus my recommendation is to get the microscope and see if flukes are
really the problem. Salt to 0.1%, this will help the fish fight off any
spring crud, it is not necessary to keep salt in the water if there aren'
t
problems, but spring is always a good time to have it there. The parasite
s
and bad bacteria wake up before the fish's immune system does.

And instead of doing those big water changes, do smaller ones more often.
One thing fish prefer is a stable environment, where the pH & temperature
do not fluctuate much. ~ jan
------------
Zone 7a, SE Washington State
Ponds: www.jjspond.us