October 25, 2005

Today's Pond Q&A

Today's Pond Q&A

In this issue:





I have been enjoying reading your articles in Water Gardening.
Since you are the koi expert, I would like to ask you a couple of

We have a 10' by 16' water pond in the last 5 years. In the last
few years, we found baby fish like koi and goldfish surviving the
northeast winter. Some of them are now 6 inches long but they are
still black in color even the goldfish. Other fish that were
given to us while small turned to gold or red & white like
sarrasas. Would the baby koi turn color by now (after 1 - 2
years)? How about the other fish that are not koi? Do we need to
do something to make them change in color?

Last spring we had 3 adult fantail goldfish along with a catfish.
We bought them when they were small and they seem to get along
for at least a year. This summer the 3 fantails disappeared
completely without any trace. Around the same period, the catfish
did not show up for feeding. Is it safe the assume that the
catfish (now about 12") had a feast on those fantails? Or, do you
think they faced some other fate? We have not seen any predators
near or around the pond. We are planning to transfer the catfish
to a natural pond next spring during the spring cleaning. We
would like to replace the fantails because we like them but
afraid they may end up like the others.

Thanks for your time reading and answering this email.

- Fred Samala

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Hi, Fred,

Thanks for writing! Sorry to say that although koi do change
color as they mature, they don't usually change all that much. If
they start out black (Magoi) there is little they can change
into. They can develop white accents and become Kumonryu, but
they aren't going to turn red or any traditional coloration. The
red and white koi start out red and white. With koi, black is an
unstable color which generally develops later in life. But a
black koi, at birth, probably isn't going to be anything else. I
have a whole pond full of them! Makes me something of an expert
on Magoi..... And there is absolutely nothing you can do to
change a fish's color. Goldfish will all begin life as a black
fish and will lose that as they grow, but koi do not. The best
(sometimes the only) way to tell the difference between koi and
goldfish, when they are young that is, is to look for the barbels
at the mouth. Koi have them and goldfish do not. If these fish
are in a sizable pond and have grown for 2 years, and are still
only 6", my guess is they are all goldfish carp and not koi. Take
a closer look to find out for certain.

As for the catfish-- I had one of those too! I learned that they
are great community fish with fish the same size or larger than
themselves. BUT they grow so quickly they usually outgrow
everything else in the pond. That makes everybody else "food". I
would think about moving the catfish now instead of the spring or
you might not have anything left by then. Have you seen him
lately? Getting big? I'll bet he is! If you go to the website
www.watergardening.com and go to my column, ask Carol, which I
was just looking at today (I just happened onto it) there is a
Q&A about catfish in a pond!




thanks for responding so quickly. Your answers and suggestions
make a lot of sense. We will now stop hoping and wondering what
color the black kois will change to. Just found 3 more baby fish
about 2" long, again black. We were surprised they spawned this
late. Is this normal? Is it safe to say if they do not change
color in a couple months that they will remain black? Regarding
the catfish, we will try catching him this weekend for

I read in Pond Doctor book that adding salt once in a while is a
good preventive practice for the fish. True? Is it better to use
regular salt with iodine or plain kosher?

I read your Q&A regarding the filters for ponds and very
interested about your filtration system.

We have an Aquascape kit with biofalls and skimmer containing the
2600 gal/hour pump and just foam filters with lava rocks. It's
hard to keep the water clean and I end up spending a lot of time
cleaning and adding beneficial bacteria a lot. The water is clear
but at night I can see particles suspended in the water(thru the
light). The water volume is about 2000 gallons with gravel bottom
but no bottom drain . I usually have a major spring cleaning and
a monthly cleaning of the foam filters. Without spending a lot of
money, how can I keep the water cleaner and less maintenance? If
I decide to spend the money, who or what company should I call
for a system like yours - vortex and bubble bead?

Again, thank you very much for your help.

- Fred



Hi, Fred,

As for the salt, NO IODINE! Make sure to use non-iodized salt. It
can be "pond salt", sea salt, kosher salt, or regular table salt,
but you don't want iodine.

The reason salt is therapeutic for the fish, although they are
not salt-water fish, is that a 0.3% solution (3lbs/100 gallons
administered over a period of several days, a little at a time)
will kill most (not all, but many) common pond parasites and will
reduce stress on fish. The way to use it is for a 3-week bath,
then do 50% water changes until the salt is gone. That is done,
for those who choose to do it, in the fall and again in spring.

I personally do not use salt in my pond for several reasons. I
don't want to jeopardize my bog plants and when doing the 50%
water changes on a 15,000 gallon pond, that is a lot of water
going down the street. You wouldn't want to dump any salted water
into the garden! I prefer to do salt dips on new fish and
quarantine regimen. What I prefer in the way of parasite
protection is to use potassium permanganate, and then only if I
see definite signs of trouble and have been able to catch, scrape
and scope a few fish to identify the problem as parasites.

I believe in using Microbe-Lift/TheraP as the "shot in the arm"
for the fish instead of salt in spring and fall and to keep the
pond clean all year long. I do water changes at 10% weekly even
into the winter as weather permits. But when the ground is
covered with snow and I cannot get out to purge the tanks, I do
drag a hose out from the house and refill the pond on a weekly
basis. Seems like the winter brings all the wildlife in the area
to my pond to drink!

- Carolyn

Happy Pondkeeping!

MacArthur Water Gardens

MacArthur Water Gardens
PO Box 3628
Alpharetta, GA 30023-3628

Posted by bfogle at October 25, 2005 12:55 AM