2025 Koi Class

Good morning. My name is Mark. They call me the Pond Guy around here. They even got me a coffee mug that proves it.

I started the business back in the late ’80s. I went to school for landscape architecture, so I’m not a veterinarian or a biologist. I’m a recovering landscape architect.

When I started the business, we did all kinds of work—patios, retaining walls, irrigation systems, trees, shrubs, and all that kind of thing.

In the early ’90s, we changed our business model and basically said no to all of that extra work and started focusing exclusively on water.

Today, we’ll build lakes, water walls like the one you see behind you with our logo, small turtle ponds, formal fountains, swimming pools—you name it. If it has water in it, we’ll build it, work with it, and learn from it.

If I’ve learned anything over the years, it’s that we learn something new every day. Water outsmarts us about 25% of the time.

So that’s our job today: to try to learn from our mistakes.

I started the business with a pickup truck and a shovel. Today, they try to keep both of those things away from me. Instead, they put me up here to talk to you guys about all the dumb things I did early on so hopefully you don’t have to repeat them.

We do a series of these classes throughout the year, covering everything from pond filtration and pond plants to the theory behind pond design and hands-on pond construction.

Today, we’re talking about pond fish.

How many people here have a pond?

I’m assuming most everybody.

When you come into Splash, you’ll see a number of different ponds and waterfalls on display. We have the smaller turtle pond inside the store, the Lily Pad Pond, our Lotus Oasis, and the big swimming pond out back.

We also have a 300,000-gallon pond behind the building that’s not part of the public garden.

We built all of this so you can come and see examples of everything we’ve learned over the past three decades about keeping ponds crystal clear, keeping fish happy and healthy, and creating the least amount of maintenance possible.

I handed out a couple of these cards. If anybody needs one, just raise your hand and somebody can get one to you.

This is what we call our ecosystem pond.

The reason you see this huge, beautiful garden here today is because we figured out how to create ecosystem ponds that are beautiful, easy to take care of, and work well in people’s backyards.

How We Got Here

My first few ponds weren’t built with the equipment or knowledge we have today.

We used to put the pump on the bottom of the pond.

All the debris would fall to the bottom, clog the pump, and suddenly the pond became a lot of work.

You’d have to scuba dive down to unclog the pump.

The pond would turn green, and you’d have all this muck building up on the bottom and breaking down into ammonia levels that couldn’t sustain a healthy fish population.

In the early ’90s, we started installing pond skimmers on the edge of the pond.

That allowed us to move the pump from the bottom of the pond into the skimmer.

That one change revolutionized everything we did.

Early on, we discovered that we had a knack for creating beautiful waterfalls, but if the pond wasn’t easy to take care of, nobody wanted it.

Once we started putting skimmers on the ponds, suddenly we could create ponds where:

That’s our ecosystem pond.

I want to spend a few minutes going through the basics so everyone understands how we keep our fish happy and healthy.

Then we’ll talk about the different types of fish—goldfish, koi, and a few others—how to take care of them, fish health issues, predators, and plants.

If you have a question, don’t hesitate to raise your hand and interrupt.

If you’re thinking about a question, there’s a good chance your neighbor is thinking about it too.

The Basic Ecosystem Pond

There are a few things we incorporate into every pond, whether it’s our small pond inside the store or the massive 300,000-gallon pond out back.

The first is skimming filtration.

When we dig a pond, we create shelves.

The very bottom of the pond is the fish area. We want that area to be as large as possible so the fish have plenty of room to swim.

You’ll also notice a fish cave in that bottom area.

We’ll talk more about fish caves later, but they’re a place for fish to go if a predator comes around.

They’re also useful during the winter when fish are hanging out in the deeper water.

Even today, if the sun comes out, you’ll sometimes see the fish hanging out in the fish caves because it’s cooler down there.

Plant Pockets

The next level up includes plant pockets.

We take our plants out of their pots and plant them directly into the pond.

We create plant pockets at the proper depth for each type of plant.

For example, we like to plant water lilies at around 18 inches deep.

We grow more than 200 varieties of water lilies at our farm in Dallas, so if you can’t find the color you’re looking for here, there’s a pretty good chance we can find it somewhere.

Longwood Gardens recently remodeled its water garden, and one of our employees went down to see it.

She came back and said, “Oh, it’s so gorgeous.”

I asked her, “Who has more water lilies blooming—us or Longwood Gardens?”

She said, “We have ten times more lilies than they do.”

So, of course, I had to send Longwood a note and rub it in a little bit.

Longwood is still a great place to visit, though.

Around the perimeter of the pond, we’ll plant marginal plants in four, six, eight inches of water, or sometimes even shallower.

Plants play a very important role in the ecosystem.

Skimming Filtration

Once we’ve dug the pond, installed the rubber liner, added the rock and gravel, and made everything look beautiful, we install the skimmer.

The skimmer is 90% of the battle.

We’re going to talk about biological filtration, but if your biological filter is too small or overwhelmed because you don’t have a skimmer, it’s not going to do its job effectively.

The skimmer physically removes about 90% of the debris before it even has a chance to settle into the pond.

That includes:

The less debris that reaches the bottom of the pond, the less work the biological filter has to do.

That’s how we get to crystal-clear water and happy, healthy fish.

Biological Filtration

Let’s talk about biological filtration.

This is the key to keeping your fish happy and healthy and reducing maintenance.

We’re going to have a quick science lesson, and then we’ll be done with it.

Any time you build a pond, you’re filling it with water, and it’s going to become a magnet for debris.

In my experience, pollen is one of the biggest nutrient sources in many ponds.

Think about it. Pollen is floating around all year long.

Yes, you feed the fish, and fish produce waste, which creates excess nutrients.

But pollen is going into the pond 24/7 whether you put it there or not.

So, if we can skim that material off the surface before it drops to the bottom, we’re eliminating a huge amount of work for the biological filter.

How the Biological Filter Works

In our biological filters, water flows into the bottom and then moves up through filter mats, bio balls, lava rock, and other media.

The bottom of the filter is essentially a swirl chamber.

We’re pushing thousands of gallons of water per hour through a pipe, and that water needs to slow down before it moves through the filter media.

Once it slows down, it flows upward through all those surfaces.

The filter mats, lava rock, and bio balls provide thousands of little nooks and crannies where beneficial bacteria and enzymes can grow.

Those bacteria consume excess ammonia.

Ammonia gets converted into nitrites.

If the cycle stopped there, your fish wouldn’t be very happy. They’d essentially be swimming around in their own waste.

The beneficial bacteria continue the process by converting nitrites into nitrates.

Why Ponds Turn Green

If you have enough bacteria to convert ammonia but the cycle stops at nitrites, you can end up with a pea-soup-green pond.

How many people have ever seen a pond like that?

Pretty much everybody.

That green water is caused by single-cell algae.

It’s the kind of algae where you put your hand into the water and your fingers disappear into the green abyss. It’s not something you can grab—it consists of microscopic algae cells.

The reason that algae grows is excess nitrites.

So we grow another beneficial bacteria, Nitrosomonas, that consumes the nitrites and converts them into nitrates.

That’s one of the reasons our ecosystem ponds stay crystal clear.

It’s not because of UV filters.

It’s not because of chemicals.

It’s because we starve the single-cell algae.

If there aren’t excess nitrites, the algae doesn’t have the food it needs to grow.

What About UV Filters?

We do sell UV filters, but we don’t use them on our ecosystem ponds.

A UV filter works by killing the single-cell algae after it has already grown.

Our goal is to prevent the algae from growing in the first place.

There are situations where a UV can be useful.

If you don’t have a skimmer or your biological filter isn’t sufficient, a UV can clear up the green water.

But that’s all it does.

It doesn’t convert nitrites into nitrates.

So you can have crystal-clear water while still having elevated nitrites that could be harmful to your fish.

That’s why we’re generally not big fans of relying on UV filters in an ecosystem pond.

Plants Complete the Cycle

Once the nitrites are converted into nitrates, those nitrates become food for the plants.

That’s the ecosystem.

The plants take up those nutrients and use them to grow.

Different plants consume different nutrients.

A red-leaf plant will use different nutrients than a green-leaf plant.

A water lily uses different nutrients than a taro or iris.

That’s why having a variety of plants is so beneficial.

String Algae

Anybody ever seen stringy, fuzzy algae?

Pretty much everybody.

String algae also loves nitrates.

So if you’ve created a beautiful ecosystem but don’t have any plants, string algae will come along and say:

“If nobody else wants these nitrates, I’ll take them.”

That’s why our ponds have so many plants.

We want those plants to consume the nutrients before the string algae gets them.

You may still see a little bit of fuzziness on the rocks or some algae around the edges. That’s normal.

But with plenty of plants, we can keep it under control.

Oxygen

The waterfall is another important part of the system because it adds oxygen.

That aeration helps all of these biological processes.

Your fish love oxygen.

Your plants use oxygen.

And the beneficial bacteria and enzymes absolutely need oxygen.

That’s why you’ll also see aeration in our retail fish tanks.

Those biological filters are highly oxygenated.

So, those are the basic components of an ecosystem pond.

Everything comes back to two things:

Physical filtration and biological filtration.

Maintaining the Biological Filter

Someone asked about the filter with rocks and other material in it.

Yes—that’s the biological filter.

You never touch it.

The skimmer is where you’re removing physical debris from the surface. That’s something you clean regularly.

If you’re a meticulous pond owner, you might clean the skimmer every day.

If you’re a bad pond owner like me, maybe once every three months.

The biological filter is different.

That’s where the lava rock, bio balls, and other media live.

That’s the bacteria house.

The bacteria are in there having a big party.

Water comes in with ammonia, and the bacteria go to work processing it.

The only maintenance we generally do on that biological filter is add beneficial bacteria.

Beneficial bacteria occur naturally in your pond, so even if you never add any, there will be some there.

But we recommend adding fresh bacteria regularly.

Why?

Because water temperatures change, the sun comes out, clouds move in, rain happens, and the environment is constantly changing.

Adding fresh bacteria helps keep the population stable.

And you’ll notice a theme today:

Fish love stability.

They want:

They’re very adaptable, but stability is extremely important.

Dosing Systems

Instead of remembering to add bacteria once a week and then forgetting for two weeks and trying to catch up, we started installing dosing systems.

The dosing system has a small pump that automatically adds beneficial bacteria to the pond.

We have two different treatments called Maintain and Clear.

You can even control the dosing system from your phone.

It’s not magic.

The benefit is simply consistency.

The ponds with dosing systems tend to look more polished, and the fish tend to be happier and healthier because the water quality stays more consistent.

On a typical pond, you’ll only use one or two bottles of treatment per year, depending on the size of the pond.

The dosing system uses such a small amount that one bottle can last an entire year.

It’s highly recommended.

Other Beneficial Bacteria Products

If you don’t have a skimmer, a lot of debris is going to settle on the bottom of your pond.

Even if you have a skimmer and it’s doing a decent job, you can still get sludge building up on the bottom.

That’s where a product like Sludge Cleaner can help.

We also have pond gummies, which contain live-culture bacteria.

When we start our fish tanks for the season, that’s one of the products we use to jump-start the system.

So there are different ways to help establish or stabilize the biological system.

Types of Pond Fish

Now we get to the fun part.

Once we’ve built the pond, we’re going to stock it with fish.

How many people have goldfish?

Anybody have ponds with bluegills, bass, or minnows?

Our back pond has bass, bluegills, minnows, and all kinds of native fish.

We kept the koi out of that pond.

We also have a couple of turtles, although I don’t know how many.

Somebody said there are three.

I’ve only ever seen one at a time, and all three supposedly look identical.

So I don’t know if there’s one turtle that just keeps moving around.

That pond was specifically designed for native fish.

Common Pond Fish

Most of our ecosystem ponds contain:

Orfe

Orfe are long, slender fish that some people call golden trout.

They’re a nice addition to some ponds.

Catfish

We sometimes use catfish in ecosystem ponds.

However, I have a word of caution about them.

We’ve seen catfish attack koi because they’ll eat just about anything.

We’ve had multiple ponds—probably dozens—where catfish have actually eaten the eyes out of koi.

So suddenly you’ve got a pond full of blind koi.

I love catfish. They’re cool fish.

But after seeing that happen, I think twice about recommending them.

Pond Sharks

Has anybody ever seen a pond shark?

I actually have one in my office.

Technically, it’s not a shark. It’s a Chinese high-fin banded shark.

It’s an algae eater that cruises along the bottom of the pond.

We call it a shark because when it swims near the surface, that high dorsal fin sticks up and makes it look amazing.

About ten years ago, these fish were extremely popular.

Unfortunately, they were overharvested in the wild for the aquarium trade.

We could get a tank of them, and they’d be gone within a week.

The problem now is that they’ve been heavily overharvested, and they haven’t been easy to reproduce in captivity.

There are people working on captive breeding, so hopefully they’ll become more available again.

They’re very docile and shy fish.

Koi can sometimes be big and obnoxious, but high-fin sharks are pretty peaceful.

Turtles and Fish

We don’t generally recommend keeping turtles and fish together.

Anybody here have turtles and fish together?

Sometimes people tell me, “I’ve got turtles and fish and they coexist just fine.”

That’s great.

But that’s not usually what happens.

At our old store, we had a turtle pond inside.

Every once in a while, a turtle would escape on a busy Saturday and we’d find it in the outside pond attacking the koi.

It would grab onto these huge koi, and we’d have to go get it.

Typically, what happens is that turtles eventually start attacking the fish.

When we build turtle ponds, we generally recommend keeping turtles by themselves and putting a barrier around the pond so they can’t escape.

If your turtles and fish grew up together and are getting along, great.

Just keep an eye on them.

Turtles and Plants

Turtles also love plants.

When we built the turtle pond at the new store, I planted about 30 beautiful plants in it.

We had water hawthorn and all kinds of flowers.

I filmed a video showing off the beautiful turtle pond.

Then I left to get lunch.

When I came back, every single plant was gone.

I thought someone had removed them.

Nope.

The turtles had eaten every single one.

So that’s another challenge with turtles.

They’ll either get hungry, bored, or curious and decide to take a bite out of something.

Our turtles now have a brand-new enclosure—a little turtle Taj Mahal.

It’s much nicer.

Goldfish vs. Koi

Goldfish typically live around 8–10 years, although you can certainly find older ones.

Koi, on the other hand, can live 30, 40, or even 50 years.

We’ve had customers pass their koi down to their children.

We’ve also had customers move and take their koi with them.

It’s not very common for somebody to call and say, “I’m moving, and I need to take my goldfish with me.”

No offense to the goldfish, but koi are a little more special.

There are stories of koi living more than 100 years, and even claims of koi living more than 500 years.

I don’t know how accurate those stories are.

I’m going to Japan in October, and one of my missions is to find the oldest koi I can—or at least the oldest story about a koi.

We’ll see how much truth there is to some of those stories.

How Big Should Your Pond Be?

One of the biggest questions we get is:

What can I put in my pond?

Our Lily Pad Pond is about 24 inches deep and holds around 800–900 gallons.

That’s a goldfish pond.

I would not put koi in a pond that size.

Unfortunately, I see ponds that size with koi in them every day.

Sometimes I see ponds even smaller with koi that are so large they can barely turn around.

Koi can absolutely outgrow their environment.

There was an old Better Homes & Gardens article from the 1970s that said fish only grow as large as their environment.

That’s not true.

A koi’s genetics determine how large it can become.

The environment determines how quickly it gets there.

So if you put a koi in a tiny pond with poor water quality, it might take longer to grow—but eventually, it can still outgrow that environment.

I’ve seen koi that are 36–42 inches long.

They’re absolutely massive.

One of the koi I saw recently was in a pond that wasn’t nearly large enough for it.

The owner had originally purchased it as a tiny fish, and it eventually became enormous.

Koi Pond Depth

Our Lotus Pond is about 36 inches deep.

That’s the minimum depth I would ever recommend for koi.

You’ll see some larger koi in that pond.

Those fish were temporarily moved there from our larger swimming pond during construction, and while they were there, they had babies.

So we decided to let them stay.

I think the pond can handle them because there are only a couple of large fish, a few medium-sized fish, and a bunch of small ones.

If we had 20 huge koi in there, the ecosystem wouldn’t be able to handle the load.

So 36 inches is a reasonable minimum depth for koi, but the number and size of fish still matter.

Larger Ponds

Our Oasis Pond is a little over four feet deep.

I love that depth for koi.

Our swimming pond is a little over five feet deep.

That pond could probably support hundreds of koi with the filtration system we have installed.

We don’t have anywhere near that many fish in there, but the system could theoretically handle it.

And yes, you can swim with koi.

I grew up playing in creeks and rivers, so I’ve always loved the idea of swimming with fish.

You’ll probably find a video on our YouTube channel of me swimming in my personal pond with 70 or 80 koi swimming around my head.

It’s a pretty strange video.

We had just thrown food into the pond, so they were all excited.

Koi are extremely curious.

I was actually sitting here last night feeding them koi crunchies with my feet in the pond.

Two of them came over and started sucking on my toes.

I thought, “Okay. Note to self: Don’t put anything in the pond that looks like a koi crunchy.”

They’re very friendly fish.

Goldfish tend to be a little more aloof.

Koi are more like dogs.

They’ll come over and say hello, and you’ll even see a hierarchy where one fish eats first and everyone else waits.

Koi Varieties

Now we’re going to get into a little Japanese terminology.

When I first started learning all the different names for koi, it was overwhelming.

So let’s keep it simple.

One of the most popular groups is called Gosanke.

That group includes:

Kohaku

A Kohaku is a white fish with a red pattern.

Sanke

A Sanke is a white fish with red and black.

Showa

A Showa is a black fish with white and red.

The easiest thing to remember is:

Black on the head generally means Showa.

A Sanke will not have that same black base color on the head.

So:

Utsuri and Bekko

Next are the Utsuri and Bekko varieties.

Utsuri are fish with a colored base and black pattern.

For example:

Bekko are generally a white fish with a black pattern.

Once you start getting into koi varieties, you can go extremely deep into the terminology.

Chagoi

One of my favorite fish is the Chagoi.

They’re relatively plain-colored fish.

They can be greenish, yellowish, or brownish.

But to me, they’re the friendliest fish in the pond.

If you see a Chagoi-type fish, it’s probably going to be extremely friendly.

Gin, Hikari, and Doitsu

You’ll also see shiny scales on koi.

That’s called Gin Rin.

You’ll also find fish with shiny skin.

On a scaleless fish, that shiny skin is called Hikari.

Another term you’ll hear is Doitsu, which means scaleless.

You’ll often see Doitsu koi with just two rows of large scales along the top of the fish while the rest of the body is smooth.

Kikokuryu

Another one of my favorites is the Kikokuryu.

Kikokuryu are a blend of different fish varieties designed to produce very specific coloration.

They often have a lot of shiny skin, so you’ll see the Hikari characteristics.

They may also have shiny scales, which is the Gin Rin characteristic.

You can find examples of all of these varieties in our tanks.

Why Are Some Koi So Expensive?

People often come into the store and say:

“Why is that fish so expensive?”

A lot of it comes down to breeding and lineage.

There are farms in Japan that specialize in producing specific varieties of koi.

One farm may specialize in Kohaku.

Another may specialize in Sanke.

Another may specialize in Showa.

Some of these farms have been doing this for hundreds of years.

When you have a thousand fish, you’re selecting the best fish to become the parents of the next generation.

Over generations, you’re creating extremely consistent bloodlines.

When you see a fish labeled Premium in our tanks, it generally means it came from a breeder who specializes in that particular variety.

We know what its parents looked like.

We know what its grandparents looked like.

We know its lineage.

That gives us confidence that the fish will maintain its characteristics as it matures.

Out of a thousand fish, maybe 900 aren’t good enough to be considered premium.

They’re still good fish, but they’re not good enough to command the premium price.

We have Japanese koi tanks that come directly from Japanese farms.

You may look at them and think, “I don’t see much difference.”

But every once in a while you’ll see one where you immediately understand.

The color is brighter.

The scales are shinier.

The pattern is more balanced.

And, most importantly, the fish has the genetics to maintain those characteristics as it grows.

Occasionally, we’ll have fish that cost:

We have customers who know exactly what they’re looking for.

They’re looking for perfect patterns, perfect coloration, and no imperfections.

If a red pattern is slightly uneven, the fish might be worth $50.

If that same pattern is perfectly balanced, the fish could be worth thousands.

That’s what you’re paying for.

It’s the lineage, genetics, quality, and potential.

Male vs. Female Koi

One question I get all the time is:

How do you tell the boys from the girls?

One way is body shape.

Females tend to have a little more body mass and wider hips.

Males tend to be narrower.

That’s a good educated guess when you’re simply looking at fish in a pond.

If we want to know for sure, we can examine the gills.

Male koi tend to have a slightly sandpapery texture on their gill plates.

But you don’t want to go around handling every fish in the tank.

Every time you handle a fish, you’re potentially damaging the protective slime coat and increasing its stress.

Another way is to turn the koi over and look at the vent.

The vent on a female is shaped differently from the vent on a male.

When you’re experienced, you can even determine the sex of very small fish.

I’ve watched people identify the sex of fish that were barely more than an inch long.

I’m always amazed at how they can tell.

Spawning

Another way to identify the sexes is to watch them during spawning season.

The males will chase the females.

If one fish is being chased by everybody else, that’s probably the female.

Spawning is often triggered by environmental changes.

The transition from winter to spring is a common spawning period.

They may also spawn after other major changes.

Interestingly, bringing new fish home can trigger spawning.

They’re in our tanks, they’re accustomed to our water chemistry, temperature, and pH.

Then you put them in a bag, take them home, and put them into an entirely different environment.

That’s a stressor, and sometimes that environmental change triggers spawning.

It’s very common for someone to tell us:

“I bought fish six weeks ago, and now I have tiny babies in my pond.”

That’s why.

The female carries the eggs.

The males sense that it’s time to spawn and begin chasing her.

They’ll nudge her to encourage her to release the eggs.

If that doesn’t work, they’ll start bumping into her.

With very large koi, spawning can become extremely violent.

We’ve had ponds with 24–36-inch koi where spawning resulted in fish being pushed out of the water, thrown against rocks, and injured.

Plants can get destroyed.

It’s a pretty intense event.

Feeding Your Fish

Let’s talk about feeding.

How many people have ever fed watermelon to their koi?

Watermelon is a great high-vitamin-C treat.

I’ve also thrown oranges into the pond.

At Splash, we use several different types of food.

One is our color-enhancing food.

If you look at the ingredient list, the first ingredient is fish.

The second is shrimp.

Then rice and krill.

It’s a high-protein food.

We consider it one of the highest-quality foods on the market.

There are other, less expensive foods where the first ingredient might be something like grain or another filler.

You’ll see the difference in water clarity because the fish aren’t utilizing those ingredients as efficiently.

Koi Pellets

We have different pellet sizes.

The larger pellet is for koi and larger fish.

The smaller pellet is for goldfish and smaller fish.

Most of these pellets float, although some will sink.

Even our goldfish will eat the koi crunchies.

If the fish are small, break the pellets in half or even smaller so they can eat them.

The larger koi can swallow them whole.

Turtles will probably eat them too.

Koi Treats

I’m working on getting some of these koi to eat directly from my hand.

It’s fun because you can hold the food just below the surface and let them figure out how to grab it.

They tend to try to eat it from the wrong angle at first.

It’s a fun interaction, and it’s also a healthy, high-nutrient, high-vitamin-C treat.

I love koi crunchies because they’re both entertaining and good for the fish.

Feeding in Cold Weather

Koi don’t have stomachs like we do.

When the water gets cold, their metabolism slows dramatically.

If you feed them high-protein food when the water is too cold, they may not be able to process it properly.

The food can sit in their digestive system and essentially rot.

That’s why we use a cold-water food during the transition into winter.

Our cold-water food is based around ingredients like wheat germ that are easier to digest.

The important temperature to remember is 55°F water temperature.

We recommend keeping a thermometer in the pond so you can monitor it.

Above 55°F, the fish are still active.

As the water drops below that temperature, their metabolism begins slowing down.

When the water is between about 60°F and 50°F, start transitioning from the high-protein summer food to the cold-water food.

In the spring, you do the same thing in reverse.

Winter Feeding

During the winter, we don’t feed them at all.

Generally, from around November through the end of March, they’re on their own.

They’re still eating naturally occurring organisms in the pond:

They’re constantly looking for little natural sources of food.

Even if they come up and act like they want some of your color-enhancing food, don’t give it to them.

You don’t want that food sitting in their digestive system when they’re unable to process it.

Someone asked about earthworms.

Sure.

They’re very high in protein.

It’s probably more fun to feed koi crunchies, but earthworms can certainly be a treat.

Food Freshness

You’ll notice that our fish food has expiration dates.

The fish may still eat food after the expiration date, especially if it has been kept dry and hasn’t spoiled.

But we recommend keeping food fresh.

The same thing applies to beneficial bacteria.

Don’t buy a huge bottle of bacteria just because it’s cheaper per ounce.

Buy enough to get you through the next few months.

We want the products to be fresh and active when you use them.

Fish Health

Sometimes fish experience stress.

Moving a fish from our tank into a bag and then into your pond is stressful.

There are also other things that can stress fish.

Fish can experience:

Even when you’re doing everything right, something can occasionally stress a fish.

When fish are stressed, they’re more susceptible to parasites and infections.

New Fish

One of the biggest stressors is introducing new fish that carry high levels of bacteria or parasites.

Those organisms can spread to the rest of your fish.

Healthy fish with strong immune systems can sometimes fight those things off.

But if the fish are already stressed, they may have a harder time.

Think about it like this:

If you’re healthy and happy and you lick a door handle at the mall, your immune system may be able to deal with it.

If your immune system is already compromised, you might not be able to fight it off as easily.

It’s similar with fish.

Watch Your Fish

One of the best ways to identify a problem is simply to watch your fish.

If you have a fish that’s normally active, comes up for food, and hangs out with the other fish, but suddenly it’s sitting off by itself and not eating, something isn’t right.

It may just be having a bad day.

Tomorrow it might be completely normal.

But it could also be something more serious.

If you call us, we’ll walk you through an assessment.

We’ll ask questions about what’s happening in your pond and with the fish.

We’ll try to determine:

Treating Fish Problems

The first thing we want to do is help the fish heal itself.

Probiotic Food

Probiotic food can help support the fish from the inside.

Salt

Salt is one of our go-to treatments when a fish isn’t acting normally.

Salt can help with some parasitic issues and can support the fish’s slime coat and osmoregulation.

If there’s a wound or certain bacterial issues, salt can also help support the fish while it heals.

We don’t recommend keeping your pond at a permanently elevated salt level.

I’d rather keep a healthy pond without salt and have salt available when we actually need it.

If you keep salt in the pond all the time and then encounter a salt-resistant parasite, you’ve taken away one of your treatment options.

It’s similar to taking the same medication every day and then discovering it doesn’t work when you actually need it.

Salt can also affect plants.

At around 0.3% salt, water lilies can start turning yellow.

At higher concentrations, you can actually kill some plants.

So that’s another reason we don’t keep the pond permanently salted.

Further Diagnosis

If probiotic food and salt aren’t helping, we can dig deeper.

We have microscopes that allow us to scrape fish and examine gills for parasites.

Sometimes we may recommend seeing a veterinarian who specializes in fish.

There are also medications and more specific treatments for parasites, bacteria, fungus, and other issues.

One of the more general treatments we use is Protect, which contains tea tree oil.

It’s a natural antiseptic, antibacterial, and antiparasitic treatment that can help support fish healing.

It can also be used in a dosing system if the entire population seems stressed or unhealthy.

Testing Water Quality

We don’t recommend testing your pond water every single day if you have a healthy ecosystem pond.

But if something goes wrong, testing becomes very useful.

Our retail fish tanks are tested twice a day because the population changes constantly.

One day we may have 100 fish in a tank.

The next day we may have 20.

So the water chemistry can change rapidly.

When a fish isn’t acting normally, we want to know:

For example, if the pH is 9 at night and 7 during the day, that’s a huge fluctuation.

Fish don’t like that.

They want stability.

Water Volume

Water volume is also extremely important.

A larger volume of water creates a more stable environment than a tiny, shallow pond sitting in full sun.

That’s one reason larger ponds are often easier to keep stable.

In fact, probably 50–60% or more of the fish problems we see are related to water quality rather than parasites or bacteria.

So we want to check the water before we assume there’s a disease.

If the testing shows a specific parasite, fungus, or bacterial problem, then we can recommend a treatment specifically for that issue.

Predators

Unfortunately, there are things out there that want to eat your fish.

Birds are one of the biggest problems.

We sell a lot of predator deterrents.

But here’s a secret:

The plastic heron doesn’t work.

Don’t buy it.

We sell thousands of them, but they don’t work.

I have customers who send me pictures of a real heron standing next to a fake heron.

The fake one doesn’t bother the real one at all.

Some of the fake owls and other plastic predators aren’t very effective either.

The birds figure them out.

What Does Work?

A fish cave is one of the best defenses.

You can build one naturally with rocks or use a manufactured fish cave.

The fish can disappear into the cave when a predator comes around.

Another option is a floating predator deterrent that moves around on the water.

The birds can’t quite figure out what it is.

But honestly, having a dog running around the backyard is probably one of the most effective deterrents.

Or having 100 customers walking around your backyard would probably work too.

Protecting Water Lilies From Koi

One question I always get is:

“I have huge koi. They’re going to eat my lilies!”

We have a simple solution.

You can create a floating ring around the lily.

Put the lily inside the ring and let it float.

The lily leaves will grow up and cover the ring, so you don’t even see it.

The koi can’t get inside the ring and get to the roots.

Turtles are another story.

They’re smarter than koi.

Don’t tell the koi that.

Turtles can sometimes climb right over the top.

We also sell a shorter version of this system to protect water hyacinth and other floating plants.

We don’t have much trouble with plants in our ponds because we’ve shown all of our koi the video about not eating plants.

I’m kidding, of course.

The reality is that once koi get two or three feet long, they’re going to destroy your lilies during spawning season or when they’re especially active.

Having a simple plant protector on hand can save your plants.

Questions

Well, I did pretty well.

I got through more than half of what I had on my list.

What questions didn’t I answer today?

Goldfish Changing Color

Someone asked about goldfish changing color.

Goldfish babies often start out black.

Then, as they grow, some will develop orange coloring.

Others may eventually become completely white.

We see color changes for a variety of reasons.

Some koi varieties can change dramatically.

For example, we have a koi variety called Kumonryu that can change from almost completely black to almost completely white within 48 hours.

Changes in water temperature or water chemistry can sometimes trigger dramatic color changes.

With goldfish, you’ll also see changes as they grow and lose scales.

For example, underneath a white scale you may see what looks like a gray or black color.

When that outer scale falls off, the color underneath becomes visible.

How Often Do Fish Lose Scales?

Someone asked how often fish lose scales.

They can lose scales every day.

It’s a normal part of growing and replacing scales.

You’ll especially notice it with some of the Doitsu varieties because they have fewer scales to begin with.

You’ll sometimes find large scales sitting on the bottom of the pond.

That’s normal.

KH and pH

Someone asked about KH.

Now we’re getting into Pond Fish 201 territory.

We talked about pH, but we didn’t really discuss what range is acceptable.

Generally, fish can be happy in a pH range around 7.5 to 9, as long as the pH is stable.

The problem isn’t necessarily having a pH of 8.5 or 9.

The problem is having it suddenly change.

If your pH is 9 and suddenly drops to 8, you can have serious problems.

What Is KH?

KH is related to the hardness and buffering capacity of the water.

It helps keep your pH stable.

Think of KH as the thing that says:

“Your pH isn’t going anywhere.”

In our ponds, we have lots of rock and gravel.

Those materials naturally help maintain stability, so we don’t spend much time talking about KH in our ecosystem ponds.

Our retail tanks don’t have the same amount of rock and gravel.

So sometimes we’ll use baking-soda-based products to increase KH and stabilize the water.

There are many water parameters we could test:

We don’t constantly talk about all of them because if the water is crystal clear and the fish are happy, we know the overall system is working.

But KH is an important background parameter because it helps maintain pH stability.

Catfish and Black Mollies

Someone asked if we carry catfish or black mollies.

Catfish have been difficult to find this year.

We like to get albino catfish because they’re pretty cool, but we couldn’t find them from our regular breeders this year.

We also haven’t had many Orfe this year.

Again, the biggest caution with catfish is that they can attack koi.

We’ve seen ponds where catfish have eaten the eyes out of koi, leaving all the koi in the pond blind.

So while I think catfish are really cool, that behavior makes me hesitant to recommend them in a koi pond.

Wrap-Up

You guys have been great.

Thank you for coming.

We’ve got two food trucks lined up for lunch, so hopefully everybody is hungry.

We’ve also got more live music coming this afternoon and more events throughout the season.

If you love what you see here and know somebody who would be interested, spread the word.

Hop on Google and give us some love there. We’d really appreciate it.

And, of course, you can call, text, or email us anytime with questions.

We’re here to help however we can.

Thank you very much for coming!

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