Lou Foxwell, known as Father Fish, is a pioneer of natural aquarium keeping and the creator of the Father Fish Method.
His approach to planted aquariums focuses on building balanced, self-sustaining ecosystems using soil substrates, natural processes, and minimal maintenance. The Father Fish Method draws inspiration from the Walstad Method and the natural aquarium philosophy of Takashi Amano.
Before entering the aquarium industry, Lou spent 25 years as a missionary, serving a congregation of deaf worshipers. He later opened a tropical fish store, where he adopted the role of Father Fish.
His passion for fishkeeping began in childhood, inspired by his grandmother from Berlin, Germany. He went on to become a founder and original board member of the National Aquarium, where he helped shape its early development and leadership.
With decades of experience across the fishkeeping world, Father Fish shares practical knowledge on planted aquariums, dirt substrate systems, and natural ecosystem balance. He also provides plants, soil supplements, and tools to help hobbyists create thriving aquariums with less effort and fewer water changes.
All clips and images are used for illustration purposes only. Learn how the natural aquarium approach changed the hobby forever. This video explores the foundational book behind the method.
Welcome,
Father
Fish
and the
Natural
Aquarium.
Well, good evening. Hello, hello.
Happy to see you all. Great to have you here.
We have J.D. the Thursday.
Now, now. Now, now. Now, now.
You're right on the edge there.
You may very well lose your rights.
We're going to delete that.
We will have no obscenity here.
Okay, well,
I did do that, didn't I?
That was horrid, just horrid.
Chum, chum, right, chum.
That's it, chum, right.
You don't know what it means, you need to learn, right?
Matt Madison.
Hello, Matt.
Let's see if there's anybody new here.
Yes, Matt is, I thought so.
Get Matt a wrench here.
Get him in the club.
This is a 100% membership club.
That is to say, there are no conditions
to membership other than showing up.
If you show up, you're a member.
You can choose not to be a member by not coming back.
But if you come back, you're going to be considered a member.
Unless you cross the line.
You don't want to cross the line.
Adam, how come you don't have a ring?
It's on a new email or something.
I don't know.
But we'll get it right now.
Hello, hello.
Good to see you.
Petra Mann.
Neil C. Vids.
J.D. Christian.
There we go.
New account.
Right.
Got it.
Gotcha.
And you're covered.
Matt Madison is covered.
This is everyone else, I believe.
Great to have you all here.
I need to talk to you, Adam.
I've got some really exciting news I want to run past you,
chat with you about.
Maybe later in the week, I'll give you a call.
Ah, you're very welcome, Matt.
So this evening,
we're going to do the fourth in a series
of four lectures on the natural
aquarium.
Now, this started as a series on AquaFred, the supplement.
And while it remains essentially focused on that,
last week we broadened it to include plants.
This week, we're going to talk about living organisms
of the animal variety as opposed to the plant variety.
So, microfauna, macrofauna.
We will get into the bacteria a bit,
although that won't be the major focus.
and essentially the effects of all
of this on a natural system
and all of it based
on the AquaFred supplement.
Let me get the mint out of my mouth so I can talk,
and we'll dig right into this.
One second.
I will take questions.
This will go on for a bit.
It's pretty involved, and then we'll do questions afterwards.
The true food web in a microcosm, by combining
a massive buffet of trace elements, such as azomite,
basalt, and structural components like biochar and clay
with wild microbes, the system is not just feeding plants,
it's fueling a bottom-up ecosystem.
So we have the fish and inverts creating waste,
the detritus and microflocs in a mixed substrate,
wild microorganisms, bacteria, protozoan,
fungi that are fed by the azomite basalt minerals,
macrofauna, microfauna rather, infusoria,
and then the macrofauna, rotifers.
and worms, the microfauna,
including microworms,
rotifers and tunicaria.
Mineral-fueled microbes are wild microorganisms
which require a vast array of trace elements
in rare earths like the lanthanum and cerium
and the zeolite to synthesize specialized enzymes
for waste breakdown.
let me say that again wild microorganisms require
a vast array of trace elements
to synthesize the specialized enzymes
that are required to break waste with their breakdown
waste so breaking waste down does not happen
in a vacuum it happens in an environment an
environment that is rich enough to facilitate
the the full process now anything breaks down
but if it breaks down purely through the action
of bacteria that it creates a foul condition
because the bacteria virtually explode
in the environment draining it of oxygen
creating a condition in which life cannot survive.
So to break down the waste properly requires
a broad array of enzymes
and other active ingredients in order to be able to support and nurture
the myriad, the literally millions of microorganisms,
both species and individuals that are required
in order to facilitate this process.
It is a community, microbial community, not a few isolated elements.
So you cannot drop a few paramecium in a tank
or a little vial with a couple of organisms in it
and expect that to really be able to satisfy
the biological needs of the system as it is
breaking down waste. It requires not only
a broad spectrum of microfauna, it requires also a broad
spectrum of mineral and elementary content.
So the principle that I have espoused from the
beginning of this is the principle of diversity.
With diversity, there is balance. There is
harmony. Each element learns to coexist with each other.
Now, to be sure, in the early stages of
this, there is a process by which certain elements
are in open warfare with each other.
But once that breaks down, as it will break down,
there are new compounds that are created.
It's called the chelation process,
in which compounds are created that are fundamental
to a natural system that is growing plants and feeding microorganisms.
So all of it works together.
What are the structures?
There are two main structures to this.
One is the mineral-fueled microbes,
wild microorganisms requiring all of the chemicals,
and the other is biochar.
Now, biochar creates a living city.
Biochar acts as a permanent microscopic apartment complex
for these wild cultures.
I was talking about this the other day in the context of charcoal
and what to do with the charcoal that no longer is active.
Leave it in the tank.
Leave it in the tank.
Unless it contains something
so dire that you have sucked out that it would pose a threat.
But if you were to have such a condition, you ought to,
number one, not put it there to begin with.
number two get rid of that charcoal don't keep it
you don't want it you don't want to go flowing
back out into the system
but the critical thing to remember is that once it has absorbed on an
atomic level on a microbial level
or beyond that on on a on the tiniest
of levels on the atomic
level or the molecular level uh to be more
to the point once it has absorbed certain molecules
that are deleterious then it begins to provide
a home for microbial activity which is able to
course through it like in a maze or an apartment building
and build its own little nests and homes
wherever and being able to feed on the the water
as it is drawn through now the water is drawn
through by virtue of i don't know if you all got
this but my microbes they move by virtue of cilia
cilia are like a thousand feet
or more to the point a thousand paddles that allow it to swim
And you can see this, if you look under a microscope,
at certain such animals like paramecium,
you'll see these tiny little infinitely numbered little tiny,
I don't know what to call them, cilia.
They're called cilia that are pulsating
and causing the animal to be able to move around.
Well, while they do that,
they're also moving water at that infinitesimal level.
Nevertheless, that water is being moved,
and it's being moved through whatever the substrate is,
which would include the cell structure of the biochar,
allowing it to further filter and further break down a waste
and also feed the host of microfauna that are living in it.
So this amounts to a perpetual cleaning crew.
This thriving microbial web serves as the primary food source
for tiny, tiny microfauna like
infusoria, rotifers, microworms.
These tiny organisms crawl through the mixed sand and mud,
constantly eating detritus and keeping the substrate from compacting,
effectively doing the mechanical maintenance in the system.
This approach completely redefines
the rigid rules of traditional aquarium keeping.
keeping. Instead of relying on pristine
artificial separation of layers, the infusion
of microorganisms allows biology to take the wheel,
creating a self-filtering, self-assembling
ecosystem that mirrors wild riverbeds
and lakes.
Most of you who are here are very clear about
this. There are many who are completely bewildered by this notion.
They cannot even conceptualize
the idea that you can have something in the tank
which would cause the system to be self-cleaning.
They're devoid of such knowledge as to be incapable
of understanding the foundations
of all biological life, which is microbial.
Now, we hear that, but what does it really mean?
Well, it means very simply that the waste,
the waste that large animals produce
is broken down into tinier and tinier
and tinier particles by microbes
that are feeding on it and releasing their own waste to feed others.
And so it's food after food after food after food
to the bacterial level, to the fungal
level, which then converts those very basic
elements into nutrition for plants, which
take up those nutrients and create
the food that the larger animals consume.
in one form or another. If these larger animals
are strictly meat eaters, they are eating animals
that themselves are consuming the vegetable matter.
So whether it's FOF1, F2, the reality is
that all of animal life depends absolutely
for its very sustenance on plant life,
on, if you will, vegetable life, either directly or indirectly.
The dependence is absolute.
What does this mean for the aquarium?
It means that there must
be a balance of animals and plants.
Now, the reality
is that many people claim they can't keep plants alive.
Here's the truth of the matter.
If they are not keeping plants alive, they are not keeping fish
alive either, at least not in the healthiest way they can.
They are, in fact, constantly, continuously, and persistently trying
to adjust the environment that the fish are living in mechanically
by taking it out, putting new water in by this constant process
of water change, water change, water change.
And the only reason they're doing it
is because they are fouling the water.
They're fouling the water.
They don't understand that fouling the water is not a law.
It's not required.
It's rather something to be overcome.
and you overcome it with a food web that is able
to cycle everything in the tank on a continuing
basis. Now,
that's not to say that that food web is going
to feed a dozen 12-inch fish in the tank.
It will not, unless you have an extremely large environment.
A 12-inch cichlid,
an Oscar, requires
the food web of probably
as much as a quarter,
an eighth to a quarter of an acre of biofirm,
bioform of biological material
in order to generate
its food requirements. Keep in mind, you see,
when you see a large school of large fish,
they're living in a vastly larger environment,
but that environment is generating microfauna,
generating small fish, feeding all of them up
to the level of the Oscar's food, which is going to
be, at all times, fish, shrimp, other inverts,
other kinds of small fishes. They have to be fed
in order for them to be there.
What does it take to feed enough of them to provide nutrients for
that Oscar now that that eighth to a quarter
of an acre is a wild estimate and may be absolutely
off the wall whatever it is however is what it
is and i give you the the reality that if you have
half a dozen large fish in a 125-gallon tank,
your food web, regardless of how magnificent it is,
will not be able to produce enough food to feed those Oscars.
You are going to have to put food in it.
Follow this now.
When you do that, you will be overloading
the food web in the system.
You will be creating more waste than
the system is able to manage.
Now, it will do a heroic job.
it will probably be able to control all
of the detritus to the point where there will be very
little detritus left on top of the sand surface.
And in fact, if you build a food web on that,
there will be even less of it.
But regardless, it will not be possible to build a food web
that is powerful enough, strong enough,
diversified enough, big enough, large enough,
substantial enough to be able to manage all
of the waste of a large number of big fish
in a restricted environment. So what happens?
Well, you get a very slow but very gradual
buildup of organics in the water.
You begin seeing this in a couple of ways.
You begin seeing it in the water becoming
maybe not murky, maybe old, kind of yellowish,
beginning to take on a tint.
You will see it in detritus building up.
You may see it in an algae buildup that is kind of out of control,
that you can't get control of.
You can't get it all out because it keeps coming back so strong.
When that occurs, that is the time to do a water change.
So with a number of very large fish in an aquarium,
water changes remain, even with
this system, they remain critical.
You may need to do so once every three months or once every six months.
Certainly not.
once every week. So I hope that allays some
of the concern and expresses more clearly what we're
really offering here,
what we're providing and what the real nature of this system is.
In point of fact, while there are a few tanks,
I have done no water changes in at all. They're
really pretty rare. And they are, by and large,
tanks like Lucas Bretsch's tanks that have very
few animals in them. And so they're producing very little waste
that is easily managed by the
microbiota in the system, leaving the water pure.
And that can, in fact, go on for years.
More commonly, a larger number of fish in a smaller tank,
which is what I have in my store,
does require occasional water changes.
Once every three months, once every six months is about average.
there's some aquariums where i want the water
to be far more pristine such as in the discus tank
well i i will do a 10 percent water change once
a month once a month and that will restore
the condition of the water to one in which
the discus will will will be flourishing so all of
that now here's the thing
this approach it as i said it redefines
the rules of the traditional
aquarium instead of relying on a pristine artificial kind of cleaning
and water changing
all the time it creates a self-filtering
self-assembling ecosystem now we we quarantine
and we screen the wild culture first
to avoid introducing unwanted macro predators such as
dragonfly larvae so the system is set up once
the substrate is in place and it's properly capped
it's planted and some fish are put in it we
then put macro and micro fauna in the form of mulched
leaves from a body of water, which will contain
a mad diversity of all of that organic life,
all of those microbial critters.
That creates the fundamental foundation that can and should
be added to routinely,
initially for the first three to four to five months, once a week,
small amounts once a week until it gets built up.
As it gets built up, it will allow the rest
of the substrate to function at a much higher rate
to be able to carry through much more rapidly
all of the nutrients, and it will increase
the ability of that tank to maintain larger numbers
of macro-organisms, if you will, of fish and invertebrates.
It will nurture those plant roots to such an extent
that they will grow more rapidly.
They will subsume the waste in so doing
and be able to sustain that cycle at a more rapid
and a stronger and a greater rate.
Our book, let me talk about the book here
second. The Natural Aquarium.
This is what I'm talking about. All of what I've discussed
is in the book. Now, it's not in here in near
the complexity that I've been describing. It's much
easier to read, much more straightforward.
I've tried to give you the science. While this does
give you the science.
It does it in a way that is readable by the average non-scientist,
by the person who does not understand biochemistry.
So while it touches on that,
deals with it in some rather substantial ways,
it does so in a conversation in a language that is
easy and simple to understand.
It's written by some excellent writers,
researchers who understand
very deeply and very clearly exactly what's going on.
And it's sought in 400 pages to put it
together so that you will have a resource,
frankly, beyond anything else that's available
anywhere. We have two professors now
who are looking at using this as a textbook,
one on a college level and one on a high school level.
So we anticipate that's going to happen.
It's really put together by chapters in such a way
as to make it a very effective teaching tool.
so there's that the book, buy the book, it's available
on amazon um we have signed copies
available uh at FatherPritchAquarium.com so
this then is the definitive multi-decade
substrate formula the foundational recipe
that in fact has revolutionized how thousands of hobbyists
approach natural fish keeping we have reached just
with our store 20,000 we have a 20,000 customer
base we know just in the U.S. there are 20,000 people
who who are using this system right now
how many others beyond that there's no way we
are anticipating uh while we're in at Aqua Shell
this weekend talking to some wholesalers about carrying
the Aquapreda substrate
in order to make it available to a wider range of stores
so that you'll be able to get it without having to pay shipping
and maybe even able to get it a little less,
although some of our deals are a little over the top, shall we say.
But it will be available, and we will then be working
with those local stores to help them understand how they can implement
this in their own fish keeping,
and at least to create an aquarium that shows how it's done.
There will be printed material that goes out with it,
so we're going to be in a teaching format as we move this out.
The book bridges the gap between everyday hobbies
and deep biological science.
It elegantly explains how a complex, wild microorganism
food web transforms what conventional hobbyists think
of as dangerous ingredients into a completely closed-loop,
crystal-clear, perpetual ecosystem.
The Aquapretta formula makes it completely
clear why it perpetuates without deletion.
The flocculation secret.
This is the key.
The massive amount of diatomaceous earth paired
with clay powder is the structural secret of this system.
Once the wild microorganism's culture introduces its biological
glues, its EPS, this mineral mix aggregates perfectly into the sand,
preventing any cloudiness,
even as it integrates over the first year.
The massive doses of azomite
and volcanic basalt aren't just acting as plant food.
They're fueling the wild bacterial
and fungal cultures that are housed in the biochar.
Microbes require those 70 plus rare earth
and trace elements to build the specialized
metabolic enzymes that are needed
to break down heavy organic matter over decades.
carbonite engine. The ratio of dolomite limestone
to baking soda provides the exact chemical wall
needed to shut down hydrogen sulfide production
while keeping the deep substrate environment
perfectly buffered for the macrocolony.
This is one of the major crises that occurs
In so-called Wallstead systems,
there are inadequate buffers, maybe inadequate buffers
in that system, which cause it to become acidic,
creating hydrogen sulfide, which is deadly.
It kills everything, and you wind up with a dead tank.
AquaPrada contains a buffering system
that is self-perpetuating, that does not break down,
does not deteriorate, remains strong
and primal as a fundamental component of the system,
permanent, permanent.
Nothing is permanent, they say.
Well, give it 100 years.
It may break down in 100 years.
it's not going to break down in 10 or 15 or 20
or 30 or 50 years you plan to have your tank up
longer than that i hope you do i hope you pass
on your aquarium to your children and they to theirs
and then we'll learn just how good we really
are because we don't know we've only been doing this
for 25 years we do have a tank 25 years old
that is going strong producing all kinds
of life will
it continue for another 25 years?
Well, I won't be around to find out, but there are those who will,
and you'll be part of that if you're still around, so you'll know.
So here we go. We're on a journey
here, you see, a long, long-term journey.
This system that we've put together rebuilds the
rigidly, overly mechanical status quo
of the modern aquarium hobby. So we are, in fact,
offering an alternative to what has come
to be the modern aquarium hobby which is
to the best of my ability to understand it
a death cult it is the system that is wholly dependent
upon the energetic and muscular activity of hobbyists on a continuing
and persistent basis
without stopping it goes on and on and on and at some
point it doesn't go on and at that point the
system fails the fish die and it's all over how
many people do you know who have quit the hobby
because they could not sustain all
of that effort infinite at some point something failed
it broke down crashed
and all was lost now that is not to say there are never any problems
in a natural system certainly there
are but by and large they are easily managed with relatively
minor effort they don't require tearing it all down throwing it away
and starting over that
should never happen the reality
is if the system completely crashes somebody throws a can of food
in there, fouls everything, all the fish die.
What do you do? You take all the fish out, take
everything out with a net, everything that's dead,
and at that point you have a choice. You can either
let it sit there for two to three weeks,
or you can change up to half of the water. If you change
the water, it will be pure in one week.
If you let it sit there, it will be pure in two to three weeks.
Once the food for all the bacteria is gone, the bacteria disappear.
They're gone.
And the tank returns to its original state.
Now, you will have to reculture
because the microbiota will be lost.
The fungi won't.
The bacteria won't.
Anything living in an anaerobic environment,
which is all the deep stuff, will still be there.
So replace the superficial stuff.
you go back out to that creek
and you've got a big jar full of microbial activity of leaves and
mulch you bring it home
and you dump it in the tank whole thing throw it in replant the tank
with new plants and it'll be back in a week it'll be healthy
and growing and thriving in a week
that substrate cannot be destroyed it can be messed up
but it cannot be destroyed it is a
permanent condition, just as the earth,
the soil on the earth cannot be destroyed. It is a permanent
condition. It can be affected, to be sure.
It can be deprived of certain nutrients, maybe many of
them, to be sure, but it cannot be destroyed.
It remains there as impoverished as it may become.
it nonetheless is capable of coming back
from with some adequate husbandry the same in your tank
don't throw it out let it sit there let it catch
its breath let it begin to come back how are we
doing here we've got about 15 minutes i'm getting weary
the carbonate the ratio let's see did we do
this okay let's do um one more
this would be the end of it now
we're going to do four little
phases here. We're going to do rare earth catalysts,
structure lockdown, micrometropolis,
and chemical shield. Rare earth catalysts, azimuth,
and volcanic basalt supply over 70 trace minerals
and rare earth elements like lanthanum and cerium.
These do not just feed the plants.
They fuel the metabolic enzymes of the wild microorganisms
that are introduced into the system.
Number two, the structural lockdown.
Clay powder and diatomaceous earth provide a massive cache
and exchange capacity.
They act as a molecular net, binding the nutrients tightly under
the sand so the water column stays crystal clear.
Number three, the microbe metropolis, biochar,
and whatever carbon you leave in there, acts as a permanent,
non-degradable habitat for wild-cultured food web, allowing
the microbes to process fish waste into plant food indefinitely.
And the last is the chemical shield.
Dolomitic limestone provides a permanent carbonate buffer
that prevents the deep substrate from going acid,
completely neutralizing the threat of toxic hydrogen sulfide.
So that's it.
That's the lecture series.
I am having a bit of a problem right now.
Maybe I can
relieve myself.
I don't know if you
picked up on that, who's a
stone working on a shallow
indoor pond for some dwarf
crayfish and snails
that a box turtle won't have access to.
What my fish friends
recommend for plants.
What kind of turtle?
Really interesting. Anything.
Any at all. Box turtles
aren't going to eat aquatic plants.
He will eat terrestrial plants
that you might want to grow some
for him. He'll eat grasses,
so any kind of grasses will
will work wonderfully well
and I would recommend doing that I would recommend not just for the
aquatic section plants and that but also put soil based
on you can use the same soil foundation
you can use aqua preta both in water
and out of water you can use it for potted plants for atriums
for for vivariums for gardens for that matter uh
and it really doesn't cost that much to do it
If you buy the material in bulk
and just use the supplement to supplement that bulk,
you can do a very large garden area
for maybe $100 worth of material
and have it sustain itself in a way
that is relatively permanent.
Let's see, we did this outdoor pond twice.
One could become a fish pond.
Well, I can see there's been a lot going on here while I've been away.
You do play while the cat's away, don't you?
All of you.
Yeah, do join the Discord channel, those of you who have not.
It is magnificent.
It's just a remarkable, remarkable resource.
Now, truthfully,
it's nothing like it anywhere on the web, not even close.
It's a source of knowledge that's manageable.
manageable. It's accessible. You can find it.
You can get to it. You can get help doing it.
It's there as a library, and more than a library,
as a community center, but a community center
of fish keeping. So just magnificent. You must join.
You must be part of it. I think we're at
about 25,000. There are upwards of 1,000 people
on it at any one point in time, so it's a pretty
popular place. I'm going to have to shut down.
I'm sorry. My bowels are complaining to me.
I ate too much for dinner before I came on,
and it is working its way through. Praise the ecosystem.
So we're going to call it a night.
Sorry to shut off a little early. I'm done here. If I don't
make it quickly, I may not make it at all.
God bless you all. Love you all, and see you in the morning
Bye for now.