Zen and the Art of Pond Ecology
Ponds are like people; no two are ever alike. Each
one has a unique set of variables or characteristics which set
them apart from others. Each one requires personal attention
to be understood. Although each one desires to achieve a state
of harmony or balance, each has a peculiar way of doing it. The
individual expression which sets each apart is what keeps life
interesting. It seems that people and ponds do have much in common.
Maybe this is why we are so drawn to the pond. Most of us would
agree, sitting by our pond after a busy day, brings a sense of
peace. I think ponds help balance our lives. Achieving balance
personally is important because it leads us to a sense of sanity
or stability. However, achieving balance takes work, planning,
persistence and time. Likewise, creating balance in our ponds
means establishing a stable system and a consistent maintenance
program which will run along smoothly without a lot of trouble.
It means creating a basic stress free environment where the organisms
involved are in harmony with one another. Creating pond stability
is within the realm of preventive care. It is taking the long
view on things and not just demanding instant results. It requires
patience and persistence. Our goal is a pond in dynamic health;
but health is not just the absence of disease, it is the presence
of vitality. Health is a koi pond where the koi can actually
grow and improve. Koi that live for a few decades rather than
just a few years or months; koi that are not constantly weakened
and threatened by infections. It's a water garden where the water
plants are vibrant and flourishing and require frequent trimming.
Algae is indeed present and part of these pictures. Bacteria
is also properly cultivated and controlled, in the filter as
well as in the water. Protozoans, worms, aerobic and anaerobic
bacteria, pathogens, algae, plants and fish are in proper proportions.
They are in a state of dynamic equilibrium where the health of
one organism is directly affected by the health of all others.
This is what I call Living Water.
The dictionary meaning of the word "stable",
besides being a place to keep horses, describes "the
ability to remain unchanged in form or character; and an ability
to recover equilibrium after being slightly displaced; and, not
readily decomposing or changing".
I for one have to admit to more than slightly displacing
the stability of my ponds. We are usually the ones responsible
for throwing our ponds out of whack. Then we expect instant results out of mother nature to bring
it back. There is a truism in aquatics which states that "nothing
good happens fast". When we want instant results, we do
things which we later regret. But that doesn't seem to matter
when our pond suddenly goes green right before we have a big
party. Which reminds me of another truism which is" Ponds
always turn green right before a big party". But that is
Water stability is the prerequisite to balance. Stable water
conditions promote good water quality. Stable pond conditions
determine how long it will take for mother nature to reach a
state of dynamic equilibrium. The microorganisms, plankton, algae
and plants and fish depend on a stable water chemistry in order
to function properly without constant disruption. Most organisms
in the pond are quite capable of functioning outside of perfect
preconceived notions. What they are not good at is change.
Endless change within the water affects all organisms negatively,
not just the fish. The fish depend on these multitude of organisms
to condition the water. Constant change within the pond chemistry
and environment creates antagonism. The good bugs are out of
balance with the bad bugs. The fish are usually the ones to pay
for this antagonistic environment.
What does water stability have to do with
As I mentioned, stable water conditions promote good
water quality. A lot of what we call good water quality is created
by the action of bacteria and microalgae decomposing the fish's
waste products. These make up the interactive soup called Living
Water. These microorganisms are inhibited by chemical and physical
changes because they must adjust and this takes time. The
organisms are not flourishing simply because all their energy
is going into adapting. Thus, our fish are swimming in a
soup where natural microbial balances are out of check. *Mind
you, your test kit may read perfect water quality but the "Living
Water Quality" is in a state of antagonism. We can say
that the biological stability is upset. Biological stability
keeps bad bugs in check.
All too often we make changes to the pond to satisfy a preconceived
notion of "good water quality" or to fix an algae problem or
treat sick koi. In the process we can take a step backwards.
Because in the very act of trying to make things right, we disrupt
what is present. We disrupt the existing stability to satisfy
a preconceived notion of what stability should be. Conditions
in the pond may not be perfect, but the organisms within are
already adjusting to it. Our changes for the better must not
do more damage than good.
Water quality guidelines of which we are very familiar; ph,
ammonia, nitrite, oxygen etc.
are given as an index, not as an absolute number. You will wear
yourself and the fish out striving for perfect numbers. Daily
observations and flexibility coupled with small careful changes
often give faster results. The koi will tell you if there is
a problem. I have seen many ponds where the water quality numbers
were not good but the koi appeared happy. This does not mean
that we should not strive for better numbers. It does mean we
need to proceed with caution and gently make small corrections.
It is up to us to provide the correct environmental conditions
conducive to stability and at the same time give us desirable
This reminds me of a time when my breeder, Mr. Nagata, was
in our shop with some very nice koi. I had tested the water and
it registered fairly high nitrites. The koi actually looked quite
fine but I did not want his fish to get sick. So I proceeded
to make a very large water change of 50% to improve conditions.
Mr. Nagata came in and saw what I was doing and yelled
"What are you doing?" "This is no good,"Very
bad". Of course I responded that I was correcting the nitrite
problem. He just shook his head in disbelief that I would make
such a big water change. As it turns out, the koi were fine and
a better course of action would have been to make a smaller water
change and gently clean the filter. This would have supported
the nitrifying bacteria and the Livinig Water Quality better
than the big water change. As it turns out many nitrifying bacteria
are in the water itself. A big water change can stunt the nitrifying
bacteria and often simply prolong the nitrite problem. The large
volume of new water is drastically different from the Living
Water Complex. The large water change may indeed dilute the nitrite
but it also dilutes the bacteria who must eat the nitrite. Further,
since the new water is sterile, full of chloramines, a different
pH, a different temperature and oxygen level it actually inhibits
the remaining bacteria. The koi were in less distress with the
nitrites than with my corrective actions.
Needless to say this started me thinking about my preconceived
notions and about the concept of Living Water.
The Concept of Living Water
When we sit back and enjoy our ponds we focus on the
obvious fish and plants. However, what we are really looking
at is a tremendous soup of various organisms all
striving for a harmonious existence. We test the water and it
checks out good. But what is really happening is a complex dynamic
chain of interdependent relationships, from ions and molecules
to microorganisms, plants and fish. Each ingredient plays a role
in the individual characteristics of your pond. No two ponds
are ever alike. When water is confined, it's components begin
to reconfigure themselves, developing a unique condition and
different from it's original state. Every water change or manipulation
by us will affect the water chemistry and organisms, good or
bad, depending on the degree of change. Every action we take
or do not take has a consequence. You have heard it said that
to be a successful koi keeper you must be a good water culturist.
Or, "Take care of the water and the water will take care
of the fish." I am sure you have also heard that "Clear
water is not always healthy water". I would like to extend
this idea to: "Water which tests good does not always have
healthy koi". I often hear this complaint; "My koi
are all sick but my water tests perfect".
Living Water is the caretaker of our fish. Living water is
the bacterial and planktonic soup which supports our koi at the
top of the food chain. Actually a tremendous part of the pond's
biofilter are the organisms in the water itself. I have an old
Nichi-Rin magazine which states that nitrifying bacteria are
free floating in the water. The same article goes on to state
bacteria which colonize a "proper" filter system will
condition the water in other ways like giving water clarity through
phosphate removal, nitrate removal, carbon recycling, etc. The
filter and the Living Water are in a continuous relationship
where one affects the other. There are many types of bacteria
in the pond which do other jobs besides just nitrification. This
hobby seems to focus on the nitrifying bacteria with little regard
for the tremendous populations of other very important bugs.
Remember the beer commercial, "It's the Water".
Consider this, if your filter makes up 10% of your pond volume;
that leaves 90% Living Water. I want to mention one of the ponds
we have maintained for over 7 years. This pond has no biofilter
and no U/V and gets 8 hours of sun per day. The filter consists
of a sump with screen in it to extract solids. It is approx 3000
gals and holds 15 large koi. This pond is totally under filtered
with no plants and yet tests zero ammonia and nitrites and yes
the water is crystal clear.. The bacteria and algae in the water
and on the walls of the pond are doing the job. Now this is where
I say, "Don't try this at home folks.". This pond did
not achieve this condition over night. It is over 15 years old
and it does have a continuous 5% daily water change.
Happy, balanced, Living Water acts as a natural probiotic. Probiotic
bacteria is nothing new. In nature it is called bio-diversity.
Natural ponds have such a tremendous diversity of organisms that
no one pathogenic organism can take over. It is only when we
put our koi into crowded unstable conditions that they break
down and the pathogens can take over. Living Water is the concept
we are using when we add probiotic bacteria like Lymnozyme to
Quite often mother nature's idea
of harmony or balance is nowhere near what we want. Mother Nature's
answer to dynamic balance usually includes algae. Possibly, lot's
of it. Algae is a wonderful organism of which we are deftly afraid.
In fact, some people are such "algaephobes" that in
the process of trying to eliminate algae from their pond they
kill all their koi. "GUILTY!" . Planktonic algae is
part of the Living Water complex, it has to be. Algae is just
making up for excess nutrients. When the Living Water or the
filter bacteria are not functioning, the algae flourishes. On
the other hand, the end product of biofiltration is nitrate.
Algae is only completing the filtration process. Yes, it is possible
to have a pond in full sun without any U/V sterilizer and have
very little algae, sometimes it is easier said than done. Living
Water is the concept we are using when we add bacteria and enzymes
to a pond to control algae. Many factors are involved, including
the age of the pond, the filter system, the pond husbandry, the
fish load, aquatic plants and the Living Water Quality.
Don't try to kill algae. Algae
is inevitable and desirable. Learn to appreciate algae. It is
making up for lack of filtration. In some ponds algae IS the
filter. Algae grows due to excess nutrients, sunshine and lack
of bio-competition. Minimize algae occurrence with proper filtration,
aquatic plants and/or small frequent water changes. Use enzymes,
barely straw, shade; non antagonistic methods. Use algaecides
as a last resort. Ultraviolet sterilizers assist proper pond
and filter designs. We are making the transition from sterile
thinking to stable living thinking. We have seen that what we
do to the water, we also do to the fish. Our goal is to achieve
maximum water quality by controlling stability within the system.
Now we will discuss correct techniques and pond systems which
are conducive to stability and lead us to good Living Water Quality.
How do we establish and maintain water
Each pond has individual characteristics which control
it's ecological stability. A simple water garden is very different
from a show quality koi pond. Most ponds fall somewhere between
these two extremes. Creating stability means knowing the limits
of your system. If you exceed the limits you will pay. Some of
us only find our limits by exceeding them. "GUILTY!"
You will get in trouble if you try to apply one pond philosophy
to all ponds. Each pond will have to achieve stability in it's
own way. The bottom line is to be flexible; understand the principles;
develop your experience and adjust your decisions based on daily
I think time is one of the most important elements to achieving
stability. Mother Nature just doesn't work fast. I think many
ponds are not really well established until after 2 to 3 years
of good management. Your water may be clear and your test kit
may have good numbers within 3 to 6 months, but true ecological
stability is more than this. It's no wonder so many people fail
when they are starting out. We want an instant pond. We want
a pond that looks like it is 5 years established and we want
it NOW. Furthermore, we expect this from a poorly planned and
designed system. Then we expect it to do things of which it is
Planning and Sticking to the Plan.
What do you want from your pond? A water garden; an ornamental
pond with koi and plants; or a show koi pond. Each of these 3
"types" of ponds has a specific goal or desired environment.
Each has specific requirements in order to achieve this goal.
Each of these "types" of ponds also has certain limitations.
When we exceed these limitations or deviate from our original
goal we can expect problems.
You would not build a beautiful water garden with many delicate
aquatic plants and then throw some koi into it. Even small koi
will grow into big insatiable koi in a few years or even months.
Would you make a pond as a large koi display and then throw in
one water lily? Sure, if you like to waste money and clean up
dirt. Likewise, you would not put a small filter on a koi display
and expect it to strike a balance. Nor would you build a water
garden and forget to add the proper number of oxygenating grasses.
If you leave the proper ingredients out of your intended system
it will not function as intended and you will be faced with modifying
the system to accommodate your new requirements. The trouble
is, most of us do not know the limitations of our systems and
we basically just WANT IT ALL. I think it is important for us
to decide what type of system we want and then do the research
and take the steps to achieve it.
All 3 of these types of ponds can be very successful when properly
built and maintained. They can also fail quite disastrously when
limitations are exceeded. They are successes or failures for
the same common and basic reasons. We will now discuss some of
the common ingredients
Sheer volume of water is probably the single most important element
to achieve water stability. Most ponds are too small. A large
volume of water has greater dilution of wastes, is more temperature
stable and the chemistry changes more slowly. Size does matter!
Volume makes up for a lot of mistakes. Large ponds have healthier
fish and less disease. Make your pond as big and as deep as you
can the first time because I guarantee that you will always wish
it was bigger after you are done building it. Always!
A water garden with only a few goldfish can be small and
hold as little as 10 to 100 gallons. A water garden has better
gas transfer when it is shallow, say 18" to 24" deep.
An ornamental pond with plants and koi should be 2 to 3 feet
or deeper and incorporate shallow areas for plants. Size should
be closer to 1000 gals or bigger.
A full fledged show quality koi pond would have few or no plants
within the pond and be 4 feet plus in depth and averaging over
Sun is a factor. A pond with lilies will require a lot of
sunshine. Bog plants require less sun. Koi fish do not do well
out in full sun and require shade from midday sun. Direct sun
will heat your pond in the day and likely go cool at night. Shade
gives temperature stability. You will have much better control
of your algae if your koi pond is shaded.
POND SHAPE AND CIRCULATION
Simple pond shapes are more easily cleaned. Simple shapes with
good water movement will not have stagnant areas. Oxygen is a
major key ingredient to stability. Stable, Living Water depends
on stable levels of oxygen 24 hours a day. Good circulation creates
a homogenous mix of oxygenated water. Furthermore, good water
movement facilitates collection of debris for removal and filtration.
I think it is important to note that some pond designs require
more circulation than others. Namely, these are the types of
ponds which have gravel on the bottom of the pond. These systems
have a higher circulation requirement to prevent debris from
settling and to promote aerobic conditions within the gravel.
Big pumps make gravel bottomed ponds work better. On the other
hand, a water garden requires little movement because fish loads
are very light and food going into the system is minimal or absent.
Koi display ponds have central drains and self cleaning designs
and may only require a gentle current with smaller pumps to circulate
efficiently. The shape of the pond itself is focused on removal
My favorite subject! This is the next item which is almost always
too small. Again, size does matter! How do you expect to achieve
stability with a biofilter that requires weekly cleaning?
When a biofilter is too small for the waste load of the pond
you will be cleaning it too frequently. The good bacteria will
be washed away too frequently.
Try these filter sizes:
A water garden filter gallons should be 2% to 5% the volume
of the pond. 1% to 3% as media.
An ornamental koi/plant pond filter gallons should be 5%
or greater depending on fish load. 3% as media.
A full fledged koi display pond filter gallons should be
10% to 20% the volume of the pond. 6% to 8% as media.
When you install a prefilter ahead of the biofilter you just
made a quantum leap in achieving stable Living Water Quality.
A good prefilter prevents solids from reaching the pump and biofilter.
Now you can clean the prefilter without disturbing the biofilter
bacteria. The biofilter bacteria are very slow growing and are
easily lost in vigorous frequent cleaning. A good filter system
would require weekly cleaning of a prefilter and cleaning the
biofilter once or twice a year! This is the difference between
filtration and water purefication. This is a very important concept
to understand. Filtration is the removal of solids from the water.
Purefication is the conditioning of the water by the action of
bacteria, microorganisms, algae and plants. As the water flows
through the biofilter, it is in contact with large numbers of
bacteria. These bacteria not only consume ammonia and nitrite
but recycle all the other dissolved organic and inorganic wastes
like phosphates and carbon based molecules and left over small
solids which past through the prefilter. These bacteria grow
on and in between the media, layer upon layer in a bacterial
matrix that becomes a little universe all it's own. This stable
population of bugs requires good oxygen flow and stable conditions
to flourish. These bugs may take 6 months to a year or more to
fully establish. Frequent "disruptive cleaning" of
the filter media washes away stable colonies of bacteria. Large
filters will bounce back more easily than small ones. Ponds in
very cold climates may rely on many aquatic plants for bilfiltration
since the bacteria often freeze in the winter and a biofilter
is restarted every year.
Ponds with gravel on the bottom do provide
a tremendous surface area for Bio-filtration. However, heavy
feeding of large koi populations along with poor circulation
will build up overwhelming solids within the gravel. The bacteria
can only digest so much. Sooner or later you will have to disturb
this muck to remove the build-up.This is when you
have exceeded the limits of this system. Please remove your koi
during this process. This "disruptive cleaning" affects
stability. The pond will indeed readjust. The questions are;
what effect will it have on your koi? What effect will it have
on your algae balance? How long will it take to regain stability
and balance? Time will set things straight with the algae. When
done carefully your koi will readjust too. Worst case scenarios
are sick or dead fish and algae blooms with a vengence.. These
systems are fine if you keep fewer koi and your circulation prevents
most of the debris from collecting in the gravel. Less than 3/4"
deep of small 1/8" grain gravel will also prevent waste
buildup. Small grain size and shallow gravel bottoms can be mouthed
clean by koi. Do the math and you will see that this amount of
gravel on the bottom is equal to 3% - 5% of the pond volume which
is similar to what I recommended for media in an external filter.
The difference is in how we prevent solids build-up. An external
filter system with a good prefilter does not require disruptive
cleaning. For better luck with gravel bottom ponds, keep your
skimmer prefilters clean and provide excellent circulation to
prevent solids from gathering on the bottom.
Some of the bacteria in the bio-filter and gravel bottoms
consume high quantities of phosphorous. In fact, given stable
conditions, some of these phosphate eating bacteria can actually
grow faster than algae. They are capable of digesting enough
phosphate that the algae just starves. This is how a pond clears
itself of green water or hair algae when the system is given
time and stability. Frequent "disruptive cleaning"
of the BIO-filter or gravel bottom is antagonistic to stability.
This is one reason why ponds go green after a vigorous filter
cleaning. Improper filtration is also the reason ponds need big
A proper filter size and design greatly reduces the need for
Disruptive Cleaning and Disease.
Most fish ponds have a higher level of nitrogenous waste than
would be found in nature. We keep too many koi and we feed very
concentrated, protein rich koi pellets. This means that our filters
and water tend to have a high count of proteolytic bacteria which
consumes these wastes. These proteolytic bacteria are growing
in very high concentrations in the biofilter or gravel bottom.
These bugs do not belong in the pond water on the fish. When
we disrupt a biofilter or clean a gravel bottom, we potentially
release these proteolytic bacteria into the pond. They are more
than happy to continue feeding on proteinaceous material, only
this time it is your koi's skin. This is one good cause of ulcer
problems. Many times I have seen koi in great shape until the
biofilter was cleaned. This is another reason why a proper filter
design is important. A good filter design cleans easily without
excessive disruption. A good design lets go of the dirt with
minimal impact to the bacteria. A good design does not release
toxic filter by-products or proteolytic bacteria back onto the
I remember a pond which looked very good and the koi were
healthy. However, the gravel biofilter had not been deep cleaned
for over one year. Furthermore, it had not been completely taken
apart for over 5 years. This bio chamber had a good settling
tank ahead of it but we still assumed it would be very dirty.
We completely removed the gravel and to our surprise it was not
dirty at all! The interesting part was after we "cleaned"
it and turned the filter back on, all the koi huddled in the
opposite corner as far away from the filter as possible for over
one week. Fortunately, the koi remained healthy, but this does
show that we released some very uncomfortable chemicals or bacteria
which really bothered the koi. Had this filter been full of black
anaerobic sludge, I cringe at the thought of what may have occured.
The Case for Multi-Chambered Filters.
In general, multichamber filter systems are more stable than
a "one tank does it all" approach.. You can clean one
of the chambers at a time and thereby not disturb the entire
system. When you clean individual chambers you are less likely
to flush loose waste and bad bacteria back onto the fish. Chambers
toward the end of the system can literally stay clean. The bacteria
in these systems can grow in peace and truly stabilize. Water
quality produced by multi-chambered filters is the best. The
best water quality is achieved when your filter is gravity fed
and the pump is at the end of the system. I have said it a thousand
times, "keep the solids out of your pump". You instantly
pollute your water when the fish waste goes through the pump.
This creates an endless list of potential problems including
hole disease and algae problems. In my experience, the advantages
of a large, gravity fed, multi-chambered, non-pressurized filter
put them at the top of the list of choices available today.
A well designed multichambered filter can be highly successful
with many different types of media including stone. Various filter
media are available which are very easy to clean of dirt without
dislodging much bacteria. Japanese mat in a honey comb configuration
does not trap the dirt within the media. Suspended solids will
have to be removed either through settling or other prefilter
tank. This keeps the dirt out of the japanese mat and it remains
aerobic. The new Matala filter mats are unique in that they can
trap dirt but easily let go of the dirt without losing too much
bacteria. The 4 various densities of Matala can be arranged sequentially
so as to trap dirt in the prefilter section and function as a
highly aerobic media in the biofilter section.
Note: Anytime you can settle debris, rather than trap it, you
will improve filter performance.
Fish and Plants
Stocking the pond with plants and or fish is the next step to
water stability. What is the first thing you can't wait to do
when your pond is built? Get the Fish!! Yea! We are in a hurry
to stock the pond. As most of you know stocking our ponds with
koi is very challenging. New ponds should try to get some basic
balance going before we add fish. We need some algae and some
bacteria before the fish go in. If aquatic plants are
to be used, add them ahead of the fish and give them a chance
to establish themselves. Give the pond some time and add an over
the counter bacterial product to give the pond a little jump
start. You may also use the aged conditioned "Living Water"
from a friend's healthy pond.
Add only one or two koi at a time whether your pond is new
or well established. Build your fish population slowly. Give each new koi a chance
to adjust, maybe one or two months. This gives all your established
koi a chance to adjust slowly to the new guys too. Remember,
your new koi is quite likely to be in a state of distress due
to the shipping and handling process. His immune system is already
compromised and he needs a stable new home environment. The easier
you make this transition on him the better.
Know Your Source.
Before buying a koi ask your dealer what his water temperature
is. What is his pH? Do his koi look healthy? When and with what
did he medicate? Does his water smell fresh? Does he have a microscope
and use it? How long has he had this koi? Was it mixed in with
any new shipments? These are questions you should ask before
you bag the fish. Good dealers work very hard to provide healthy
koi but the reins are being handed over to you. You need to decide
if this koi is really ready to go home to your pond and is your
pond really ready for this koi.
Quarantine of new koi can either contribute to stability or
disintegrate it. Most quarantine ponds are too small and under
filtered. Improper quarantine is actually worse than just throwing
new koi right in the pond. Your koi can come out of quarantine
weaker and more susceptible to disease than when first purchased.
Proper quarantine is a bonus when done in large tanks of greater
than 300 gals. You can stabilize your new koi for one month or
more and watch for signs of illness.
You must realize that every time you add koi to your existing
population you are essentially disrupting stability. Along with
the koi come their bugs. Strong and stable koi will have stable
bugs, bugs which are in commune with the fish. Existing koi and
new koi will have to share each others bugs. Often times, koi
have to get sick to acquire new immunity. This is when all hell
can break loose if your pond is overcrowded.
This factor is a critical ingredient to gaining or losing stability
in the pond. It is directly related to pond volume and filter
size. Every pond has a stocking limit. Once you have exceeded
this limit you can expect problems. Everybody wants"just
one more fish." Unfortunately, most of us will not know
when to stop. Most hobbyists find that they don't have disease
problems when they first start adding koi.because it is not overcrowded.
Once the population reaches a critical level, parasites or bacterial
infections start showing up. Of course it is always the dealers
fault. In fact, it may very well be the dealers fault because
he did not try to talk you out of buying too many koi. I find
it interesting that a given pond will continue to somehow reduce
it's population over and over again, despite our efforts to try
and push the limits. We cannot expect to randomly throw in new
koi from various sources without having a major pathogen outbreak.
Natural pathogen/probiotic balances take time. Plus an individual
system is only capable of handling limited quantities of waste
before balance and stability is upset. I am constantly amazed
at the quantities of food that koi require and the triple quantity of waste this seems to produce. Koi are not really fishthey
are "Water Pigs".
Yes, it is possible to exceed the limits for awhile. Goldfish
can live for 10 or more years and koi can live 25 years plus.
So do we call ourselves successful when we can overcrowd our
pond but the koi live only a few years? Are we constantly replacing
koi to bring our population back up? Are we successful because
we know how to give our koi antibiotic injections to prolong
their overcrowded existence for another year or so? As a koi
dealer I should probably just shut up now. However, as a koi
dealer I do have a responsibility to the koi and the hobbyist.
The fact remains, overcrowding kills koi and makes ponds look
bad eventually. The fact also remains that you can keep many
koi alive and well with above average water keeping skills, large
proper filter systems and a good diet.
Try these stocking rates if you are having continuous disease
Water Garden/Plant Ponds.
Without filter: Zero
Koi. One goldfish per 50 gallons.
With filter: Zero
koi. One to 2 goldfish per
50 gallons depending on filter.
Ornamental Koi/Plant Ponds.
Filter 5% volume of the pond; 3%
as media: One adult
koi/300 gals. 1000 gals minimum.
Koi Display Pond.
Filter 10% volume of the pond;
6% as media: One adult koi/200 gals. 2000
Show Quality Koi Display Pond.
Filter 10% or greater; 6% or greater
as media: One adult koi/500 gals. 5000
I can hear it now, "There is no way in hell that I am
going to keep so few koi!"
"That's only 2 to 6 koi per 1000 gallons! " "Besides,
I have a lot more koi than that right now and they are just fine."
All I have to say is; "Make a bigger pond. Have you ever
seen a 3 year old koi at 22"? How about a 5 year old at
28"? "Well yeah, but my koi are only like 6 inches
long!" Imagine six cute 6 inch baby koi in 1000 gallons
in 3 to 5 years from now. Plan for future growth. Koi need a
lot of room. How many Chihuahua dogs would you try to contain
in the same small space? Who am I kidding; 99% of hobbyists will
not listen to this. I do know from experience that under stocking
has never been problematic except for upsetting my insatiable
desire to have more koi. Ponds which are not overcrowded simply
do not have the incessant uncontrollable diseases present in
today's koi mania hobby. Koi can actually fight infection and
parasitic diseases without us declaring chemical warfare on the
pond. Living Water Quality is very high and stable at low stocking
Are some parasites desirable?
On the microscopic level, the bugs on a koi's skin and mucous
is another universe all it's own. The skin and mucous are in
a dynamic exchange with the Living Water around it. To say that
a koi is at one with his surrounding water is an understatement.
The chemicals in the water, the microorganisms, the fish's diet,
all affect the koi's health. Pathogens are always present. We
cannot eliminate parasites. We can minimize stress and maximize
pond stability. Medications merely reduce pathogens long enough
for the fish to regain stability. A mucous scraping of healthy
koi will usually reveal some parasites. Some parasites, like
trichodina, are commensal organisms living symbiotically on the
mucous of the fish. They eat excess bacteria and organic debris.
In a way they are like ants or spiders in a garden. Trying to
sterilize the koi will do more damage than good. We wipe out
the good bugs with the bad. A few of these bugs may indeed be
desirable. Koi breeders in Japan and around the world understand
that regardless of the parasite, it is the level of biological
stability which determines a disease outbreak. So what will you
do the next time you see your koi casually scratch himself on
the walls of the pondPanic? Should you dump in every known chemical
to eradicate the disease or should you seek clean stable water
conditions? Should you question your maintenance techniques or
filtration? Should you get rid of 50 or so extra koi?
Remember, when medication is inevitable, a stable pond will bring
Medications Effect on Living Water.
Inevitably we do things which will disrupt stability and effect
our Living Water Quality. Stability has been knocked out for
whatever reason and due to overcrowded conditions we might have
to medicate. First, we must gently encourage the pond back to
stability before we consider medications. Reduce the stress and
fix the water FIRST. Whatever you do, don't panic; panic pushes
us to do regretful things.
Basically, ALL medicines are antagonistic to Living Water Stability.
Consider these points when medication is inevitable.
Know the gallons of your system.
Know what parasite if any you are dealing with.
Use a specific medicine for a specific bug.
Treat accurately and promptly.
Do Not Over Treat or Over Dose. You will kill the Living Water
or the filter bacteria.
Formalin and potassium permanganate and salt are all over used
in the industry. Use judiciously.
Change small quantities of water after treating to dilute toxins
and improve water quality.
Sometimes it is better to medicate individual fish in a separate
bath if practical. In this way you won't impact the Living Water.
Focus on stability. Are your actions contributing to stability
or antagonism. All to often, we do TOO MUCH.
Establish a consistent maintenance program to promote stability
and ease back pain. The design of the pond should revolve around
ease of maintenance. If you set up your filter so it can be easily
backwashed, you are more likely to do it religiously. What I
see all too frequently is a pond which goes from one extreme
to another, too dirty, too clean, too dirty, too clean. Letting
the pond turn to garbage and then completely cleaning everything
will never get you to the balanced pond you were hoping for.
Alas, many pond and filter designs limit us to this kind of cleaning.
Get the right filter design and you will be in charge.
Water Changes and Filter Cleaning.
Proper water changes are extremely valuable in maintaining stability.
However, tap water is totally different from your ponds water
in pH, alkalinity, temperature, salinity, dissolved oxygen, it
is sterile and contains chloramines. Make small water changes
frequently. 10% water changes spread out more frequently are
better than big water changes done infrequently. Don't make big
water changes unless absolutely necessary. Some emergency situations
may indeed demand a large dilution. Toxic chemicals like pesticides
or paint would require an immediate 70% to 100% water change
to save the fish. A high ammonia or nitrite level would be better
controlled with 10% to 20% daily water changes and corrective
In Japan the dealers provide a continuous drip or small stream
of new water into the pond at all times. The pond continuously
overflows via an overflow pipe. This drip may constitute a 5%
to 10% daily water change. This, over time, establishes a very
clean and yet stable water condition. Of course they are using
well water. In other parts of the world we have too much clorine
or cloramine to make this a feasible option. However, we can
add up to 2% or 3% daily without dechorinating and without any
harmful effect. In fact, I know of a few ponds here in So. California
using this approach with great success and nitrate readings as
low as 20ppm with heavy fish loads. You will need an adequate
overflow pipe to accomplish this successfully.
If you cannot use the drip approach you will simply have to change
water when you backwash your filter. Crowded koi ponds or show
koi displays may need 25% to 65% or more, monthly water changes.
Be careful of chloramine. Water gardens do not require large
monthly water changes.
Don't mess with the pH too much.
Fixing "too high" or "too low" a pH can kill
fish. Understand your reason for improper pH balance. Do not
alter the pH by more than 0.2 increments daily. Establish a stable
pH which your koi can live with, somewhere between 6.8 and 8.2.
Quite often, regular water changes will stabilize pH, however
some parts of the country have poorly buffered tap water and
you may need to add some type of buffer to the pond.
We have seen that creating a stable balanced pond is a lot
more than just producing good numbers. We have learned that to
take care of the fish we must take care of the Living Water.
Good "Living Water Quality" is determined by the health
of the microorganisms in a dynamic equilibrium. The stability
of the pond, chemically and physically, determines the health
of these microorganisms. Water stability is an end product of
planning and proper design. Water stability takes time and patience.
It requires staying within limits. Maintaining stability requires
a filter system that can be cleaned without disrupting the pond.
Long term stability means developing a maintenance program that
is not disruptive. Each pond will acquire it's own unique state
of balance. Be flexible. Observe your pond water conditions and
your fish every day. You are aqua-culturists. You must learn
to culture stable Living Water. The Living Water will take care
of your fish.