updated 08/23/2008

List O' Questions

• How do I Get Rid of Green Water?
• My Fish Are Dying or Sick! What do I do?
• Will My Fish Live Through the Winter?
• How do I Get Rid of Those Little Red Worms?
• Can I Turn Off my Pump at Night?
• How Many Fish Can my Pond Hold?
• What Do I Do With My UV Unit in the Winter?
• What Equipment Do I Need for a HEALTHY Pond?
• Where Should I Locate My Pond?
• How Deep Should My Pond Be?
• What is the Nitrifying Cycle and Why is it so Important?
• What Can I Do to Make My Pond Less Work?
• Why Do You Prefer External Pumps?
• What is a Bead Filter and Why Do You "Prescribe" Them for Ponds?
• Should I Line the Bottom of My Pond with Rocks?
• Why Won't You Recommend the Side-Skimmer / Bio-Falls Type Systems?
• Can I Turn Off My Pump in the Winter?
• What Should I Look For When Purchasing a Koi or Goldfish?
• How Do I Introduce New Fish Into My Pond?
• How Can I Protect My Fish and Frogs from Pond Predators?
• How Much Should I Feed the Fish?

Quick Links:

How Do I Get Rid of Green Water?

Green Water is caused by algae, a free-flowing microscopic plant, that feeds on fertilizer in the water.  Whenever the water heats up and all of a sudden you have pea-green soup instead of pond water it is referred to as algae bloom.  There's basically 2 different ways to get rid of algae bloom.  The first way is to achieve a natural balance where the fertilizer is taken up by plants.   The second way (and most effective way) is to put in an ultraviolet water clarifier, or "UV Light" for short.  Learn more about this by reading our articles entitled, Those Low Down Green Water Blues and  Principles of Crystal Clear Water.

Emergency Room

My Fish are Dying or Sick.  What Do I Do?

This opens up a whole chapter on fish health and cannot be answered without further exploration of the facts.   The best thing to do is to go to the Online Emergency Clinic at PondDoc General Koi Hospital for emergency help or for great diagnostic help with koi and goldfish, go to our Diagnostic Center.  There's also a list of informative articles we've done about diagnosing and treatment of fish disease in our online What's Up, Doc? newsletter.  Click HERE to go there.

Will My Fish Live Through the Winter?

Most of the time the answer is yes.  It depends on where you are and how deep your pond is.  Fish cannot survive in water temperatures of 36 degrees and below.  They become semi-dormant in temperatures between 36 and 50 degrees and just hang around the bottom until the water temperatures begin to rise.  If you are in a climate where the water freezes down several inches you definitely want to place a de-icer unit on the pond.  De-icers switch on at 42 degrees and keep a hole in the ice for gases to escape.  For more information on wintering the pond read our articles, Preparing for the Plunge and Pond Heaters...Use Them Wisely.

Back to Top

How do I Get Rid of Those Little Red Worms?

The little red worms that you find in the filter material of your bio-filter are perfectly natural and a sign that your system is CLEAN.   Do not get rid of them.  Enjoy them and allow your fish to eat them.   Read more on the subject in our article, Don't Kill Those Red Wigglers, Freeze Dry Them.

Can I Turn Off my Pump at Night?

No! Not if you have fish.  Nighttime is the absolute worst time to turn off the pump.  During the day plants take CO2 from the water and give off oxygen.  At night, however, plants turn into Mr. Hyde by stealing oxygen out of the water and giving off CO2.  Aeration is vital to your fish and lack of aeration will kill.  Learn more about aeration by reading our article entitled Do You Have Enough Aeration In Your Pond?.

Back to Top

How Many Fish Can My Pond Hold?

The answer may shock you!  You probably have too many now.  With "normal" bio-filtration we say about 1 (one) 12" koi - including fins - per 100 gallons of water is pushing it or - generally speaking - 1 koi OR 2 goldfish per 100 gallons.  What we mean by "normal" bio-filtration is at least the bio-filtration capacity of a good quality bio-filter rated (by us!**) to work on a pond of your size.   Then, you must take into consideration that these 12" koi will grow!  The more you beef up your bios the more fish you can put in, however, be aware that overcrowding the pond, no matter how much filtration you have, can be a major factor in causing gill disease and other fish health problems.  You may rock along for a year or two with an overcrowded pond then one day walk out and see that Mother Nature has thinned your pond out her "way" and taken your largest and most prized fish.   It's best to thin out the population yourself before Mother Nature decides it's time for her to do it.

**The reason we say "rated by us" is because manufacturers tend to have a bloated opinion of how many gallons a biofilter can handle.  We tend to be more conservative.  In fact, as a rule of thumb, we cut manufacturer's rating in half.  For example, a filter may claim to work on ponds up to 2000 gallons but we'd probably rate it at 1000 gallons.

Back to Top

What Do I Do With My UV Unit in the Winter?

PROTECT IT!  There are glass components inside the unit that will break if water freezes inside it.  Read up on it by reading our article entitled "UV Protection for Winter".

To keep it healthy you need fish-safe liner (not roofing liner), a pump to move the water and a biological filter to create the eco-system (nitrification process) of the pond.  That's the basics.  Anything you install that helps keep the environment clean will help.  A bottom drain with an external pump and external filter will encourage all solids to be filtered out of the pond and easily removed.  A skimmer (preferably fish-safe) will continually rake off the leaves and stuff that falls and floats on the water.  Read our article The Doc's Dream System -- A Construction Guide to Backyard Ponds for a list of all components of the pond and how each benefits the system.  NOT lining the bottom of the pond with rocks will go a long way with keeping the amount of muck from accumulating between the rocks.  Read our article Turn Your Pond into a Cess Pool - In One Easy Lesson! for a lesson on what NOT to do if you want a healthy pond.  A UV will keep it clear but is not necessary if you are thinking only health-wise. 

Back to Top

The short answer is wherever you can best enjoy your pond but there are factors you want to consider when finding the perfect location of your pond.  For example, if your pond is in full sun you WILL have water so green that it looks like pea soup.  You would then need to budget the cost of a UV light.  If you locate it under trees you will have to cover it with netting during the fall to prevent a maintenance nightmare.  Wherever you place your pond you can plan to build your pond to overcome those types of obstacles.  For more pond construction planning tips, visit Pond Doc's Pond Construction Education Center.

At least 3 feet if you plan to have fish.  It helps to have a deeper pond in winter and it protects the fish better from blue herons - a very common predator of koi and goldfish.  If you want hardy water lilies you'll be surprised to know that you'll have bigger blooms and pads if you place them deeper - at about 5 feet deep for many types of hardy lilies.  Again, visit Pond Doc's Pond Construction Education Center for more information.

Fish and dying plant material create waste in the water called ammonia and nitrites.  Ammonia and nitrites will kill fish and help make an unhealthy pond environment.  Ammonia and nitrites are converted to harmless nitrates (fertilizer) by nitrifying bacteria.  Nitrifying bacteria, Nitrobacter and Nitrosomonas, need to be alive and well in your pond's biological filter so that they can continually convert the waste into fertilizer.  For a more in-depth explanation of the nitrifying cycle read our article Mother Nature's Balancing Act - The Nitrifying Cycle.   You DO need a biological filter in your pond if you want continually healthy fish.  Bad water quality is the most common problem with koi or goldfish health.  You could lose your whole pond full of fish with just one ammonia or nitrite spike! 

Back to Top

By installing the right equipment you can make your pond a low-maintenance pond.  An external pump and back-washable bead filter will go a long way in making it easier to maintain.  It's not hard to retrofit an existing pond to make it less work on you so don't think you can't make it easier for yourself if you already have a pond built.  Read our article RetroFit Your Pond for Fish.  It should help!  If you are in the process of building a pond you can make your pond operate with the lowest maintenance possible by following a few really neat tricks of the trade such as using eduction jets to "sweep" the dirt to the bottom drain.  Find these tips and in-depth instructions at Pond Doc's Construction Education Center.

Unless you have a small pond less than 500 gallons we would almost always go with an external pump for a plethora of reasons.  Yes, they are more expensively priced but will cost you less in the long term.  They last longer.  You can replace parts instead of the whole pump.  They generally use less electricity.  Those are the monetary reasons.  The fact that you are not lifting out a heavy, wet pump to clean it every week or so is worth its weight in gold!  Read more on our love of external pumps in our article, Singing the Praise of the External Pump.

Back to Top

A bead filter is the most low-maintenance method of mechanical and biological filtering available today.  It is superior to other filtration methods because it takes 5 minutes out of your week to maintain and you don't even have to get your hands wet when cleaning the filter.  It looks like a pool or sand filter but it's far from a simple pool filter.  Just about all bead filters, including our ProBeads, are made from tanks originally meant for installation on pools.  The inside of the filter is where the difference lies.  Tiny floating beads trap dirt and organics as pond water flows through the unit.  The solids are then backwashed out of the filter through the waste port.  The waste water is great fertilizer for your garden so it makes ecological sense.  While keeping the pond cleaner the bead filter gives you biological filtration as well because nitrifying bacteria colonizes on the tiny floating beads.  Bead filters are a bit expensive but they last "forever" requiring only occasional maintenance and replacement parts.  Cheaper filters tend to tear up within the first 2 to 3 years - some even sooner.   For a more thorough examination of bead filters see ProBead Q&A.

The answer to that question is a resounding NO, NO, Never!  Many books, how-to-videos and installation instructions for pond system kits out there will tell you to line the bottom of the pond with rocks.  They have their reasons for saying it.  Rocks hide the liner and the "crap" that naturally collects in a pond.  Their systems are not designed to remove the muck off the bottom so this muck has to be hidden somehow.  Basically what happens is that the muck collects between the rocks and you don't see it so you don't think your pond is dirty.   The manufacturers of these systems will tell you to use Microbe-Lift or another enzyme-type product that eats sludge and processes waste.  They know that if the muck that builds up between the rocks is not "processed" it will turn your pond into a cess pool.  In other words, they are instructing you to build yourself a waste water management system - and a very inefficient one at that!  What it all boils down to is that you can't keep a pond clean and healthy with rocks on the bottom.  Read more about this subject in our article: Turn Your Pond into a Cess Pool - In One Easy Lesson!  

Back to Top

How do we hate thee - let us count the ways...  Actually, we don't hate these pond systems we just know how it is to deal with the fish health problems these systems create.  They can work well on water gardens that have no fish in them but they do cause many problems for koi and goldfish.  #1.  Fish get trapped in the side skimmer and die - and, no, they have not come out with any gadget that safely releases them.  #2.  These systems pull water from the top of the pond, not the bottom - and, no, the optional bottom drains you can pay extra money for on these systems are not efficient by any means.  If you don't pull water off the bottom of the pond you don't circulate the water and all the muck that's down there stays down there.  The pond becomes stale and you end up with a swamp.  We equate this quite correctly with flushing a toilet from the top only.  Gives you a pretty picture, doesn't it?  #3.  We hardly call it a "filtering system".  They tell you the (expensive) waterfall part of the system is a biological filter.  Not a chance...  Two little pads do virtually nothing to create a healthy nitrifying cycle for 20 large koi or goldfish.  #4.  They brag that you "never have to clean" the filters.  I wouldn't brag on that if I were them.  It's true that you never have to clean the pads if they never filter anything out.  #5.  These same folks who manufacture the systems also advocate lining the pond with rocks.  Refer to the question above...  If you want to see how we "really" feel about the side-skimmer /bio-falls pond systems, read our article:   Landscaper's Dream - Pond Owner's Nightmare - A Look at the Terrible Side-Skimmer System.

Sure - as long as your fish are healthy.  Cold water holds dissolved oxygen better than warm water.  The fish also go through a semi-dormant stage when the water temps are below 50 degrees and do not respire nearly as much thus they need less oxygen during the winter.  We do recommend that you don't circulate the bottom waters during winter and expose the warmer bottom water in your pond to "super cooling" by exposing it to air.  If your koi or goldfish have gill problems or parasites, I would not take any of their oxygen away.  That's the only exception.  You can get lots of tips on winterizing your pond by reading our article,  Preparing for the Plunge.

Back to Top

The number one thing to look at is the fish's health.  Don't purchase a sick fish.  Do not purchase a fish that is lying on the bottom with his fins clutched to his sides, one that has sores, cuts or tears in his fins, one that is swimming "funny" or hanging out by the water return, one that is gulping at the top for air or alienating himself from the others.  Do not purchase any fish from a tank where fish are showing obvious signs of health issues, even if the fish you want looks okay.  With that said, choosing your koi or goldfish is a preference thing.  Beauty truly is in the eyes of the beholder.  I always say to buy the fish that "winks" at you.  If you are a serious koi keeper you would be interested in knowing the quality marks of the different koi varieties.  Read our article entitled Know your Koi!.

After you quarantine and treat your new fish (perhaps using Doc's Parasite Pak) you should get the new fish accustomed to the temperature of the pond water before throwing them in.  If you use bags to transport them simply float the bag for about 15 minutes.  Otherwise begin adding pond water to their holding tank until the water temperatures are within a few degrees.  Lower them gently into the pond.  Do NOT add new fish to a pond that has health problems.  For more information about new fish read our article,  How a New Fish is Like a Canary -- Why New Fish Die First.

Back to Top

Ponds that have areas that are at least 3 feet deep and no plant shelves are better protected from predators simply because they don't provide wading areas for blue herons and they don't give raccoons shelves to sit on and go fishing.  If it's too late to deepen your pond then you'll need to use several methods of protection.  They range from heron decoys to ward off the territorial blue heron to netting the pond to using a motion-detected sprayer like the "scarecrow".  You can read more about predators here:  The Dreaded Predator, the Blue Heron & Other Invaders of the Pond.

The short answer is to feed your koi and goldfish whatever they can eat in 5 minutes.  Once a day is usually sufficient during the cooler months of pond season but you may find that they welcome another feeding when it's warmer and their appetites are ferocious.  Feed them good nutrition, not fatty foods like catfish food.  The Pond Doc has his own foods that are reasonably priced and good nutrition without corn additives.

Back to Top

Purchase or Redeem Gift Certificates