5 Pond Dangers to be Aware Of

Submitted by Don Harrawood on Fri, 09/23/2016 - 08:34

By: Don Harrawood, SKAPA

Everyone who keeps a pond should review their preparedness to deal with these 5 common dangers.

Lightening Strikes

It is not common, but it does happen.  Lightening can strike your pond and kill your fish.  This photo shows the result of a lightning strike in a local pond a few years ago.  Thirty two fish met their instant death when lightning struck the pond.  Only a few very small fish survived the strike.  The larger fish are the first to die because of their larger body mass, which absorbs the greatest amount of electricity.  There isn’t much to be done in preventing this kind of fish kill; however I have seen a picture where an elaborate kind of lightning rods were installed around a pond.  Will this work. Who knows?  The most important thing is for Pond Owners to avoid danger - if you can hear thunder, you are close enough to be struck by lightning.  Water does not attract lightning, but it does conduct electricity extremely well, and a nearby lightning strike could kill or injure you, especially if you're working with anything metallic.


Fertilizers, Insecticides, herbicides

During the summer, many of us apply fertilizer to our lawns in order to get an early start on grass development.  This is a reminder that while applying fertilizers or other chemicals to your yard, avoid getting any of it into the pond water.  Also avoid insect sprays being applied near the pond.  Wind can sometimes carry spray toward the pond and contaminate the water surface.  Koi do not like fertilizer or insect spray in their water, and may die because of it.  If you have a lawn maintenance person, make sure and warn them to avoid getting fertilizer and insect spray near or into the pond water.  Check your pond bank to make sure the soil outside of the pond slopes away from the pond and not toward it.  Heavy rains can cause lawn chemicals to run into the pond when the slope does not prevent it.  Lawn chemicals and insect sprays can cause massive fish kills in ponds.

Avoid roof overhangs above the pond.  Rain water washes all sorts of contaminated material off of the roof.  When these impurities are washed into the pond, the water becomes contaminated with foreign materials that are unhealthy for the Koi. 
Avoid a heavy layer of muck in the bottom of the pond.  This is decayed material that can result in hydrogen sulfide gas in the pond water.  Excess hydrogen sulfide gas can cause Koi to acquire damaged gills and can negatively affect their immune system, which makes them prone to ulcers and other unhealthy conditions.  Keep your pond bottom clean.

Electrical Current in Water

Sometimes faulty equipment such as submersible pumps or broken ultraviolet lights can emit small amounts of electricity into a pond.  If you see and/or hear your fish jumping out of the water frequently, check for electricity in the water.  You can check by putting your finger into the water to see if any tingling feeling exists. Check as near the submersible pump as possible. Fish can die when subjected to electrical shock for an extended time.  Just as with lightning strikes, the larger fish are affected the most because they have a larger body mass for absorbing the current.  If electricity is felt, check to see if the electrical circuit is controlled by a ground fault interrupter (GFCI).  If no GFCI is present, you should get one installed immediately.  If one is present, have it replaced.

Power Failures:

Power failure is probably the most common cause for fish kills.  Ponds are generally designed for 100% run time for your pump and filtration system.  If running is interrupted for an extended time, fish mortality can occur based upon several factors;
Aeration; Fish ingest water through their gills to provide their bodies with oxygen and to expel carbon dioxide and ammonia.  Cold water holds much more oxygen than warm water.  Warm water requires aeration in order to supply enough oxygen required by the fish.  In general, aeration is accomplished by waterfalls or streams returning to the pond.  If the water flow, in warm weather, is interrupted for an extended time, fish can starve for oxygen and die as a result.  Larger fish will die first, since they require more oxygen than smaller fish.  If the condition exists for several hours, a massive fish kill can result.  When water is warm, make sure adequate aeration is available to the fish by keeping waterfalls and streams running constantly.  Other aeration is available through air pumps.

• A pond owner can lose all their Koi due to an electrical outage during a thunderstorm. The electricity at the pond can go off and be unnoticed for a period of several hours causing an inadequate supply of oxygen in the water.  Most commonly electrical interruptions during a rain storm are caused by the tripping of a ground fault interrupter (GFCI) that protects the pond from electrical problems.

If GFCIs gets wet, they will shut off the electrical circuit to the pond pump.  GFCI’s can be reset by pushing the reset button after a failure; however, if a pond owner is not aware of the circuit failure, pond water can go without aeration and ammonia removal for several hours before the failure is noticed.  Pond water in summer months is about 80⁰ temperature or more.  Warm water contains very little oxygen and needs to be continually aerated in order for Koi to survive.  When electricity goes off, water flow stops and aeration ceases.  Some safeguards for electrical failures are listed below:
• If the pond has more than one pump, put the pumps on separate electrical circuits.  The dual system will increase safety.
• If the pond has a waterfall, add an electrical driven aerator and put these on separate electrical circuits.
• During power failures, one can use a portable gasoline driven generator to provide electricity during the power failure.  These small generators can be purchased locally.  
• An audible alarm can be installed to notify the pond owner when water flow stops.
• Another non-mechanical solution is to add 0.03% Hydrogen Peroxide to the pond water to supply oxygen.  Apply 0.03% Hydrogen Peroxide at the rate of ONE QUART to FIVE THOUSAND GALLONS of pond water.  Dilute this in a large container of pond water and spread along the edges of the pond.  Agitate the water with a stick or paddle to spread the concentration of Hydrogen Peroxide as evenly as possible.  An alternative is to pour some of the mixture in the water every few minutes rather than all at once.   Keep it away from the fish as much as possible since this concentration when not mixed well with the water can be caustic to fish gills.  This concentration should supply adequate oxygen for 3 or 4 hours .  A quart of 0.03% Hydrogen Peroxide is handy to have on-hand just for this type of emergency. If Koi are starving for oxygen, they can be seen at the surface gulping for air.

High or Low pH

pH is the value of acid versus alkaline in pond water.  A pH of 7.0 is considered neutral; whereas below 7.0 is acidic and above 7.0 is alkaline.  Koi flourish in pH values from 5 to 9 without any problem.  Koi subjected to water outside this range of pH values can and will experience grave stress and can die.  Normally the pH value of pond water takes on the value of the source water and is not a problem except for a couple reasons:
• New concrete ponds will inherently show a high pH value as high as 12.0 or even higher because pond water leaches the cement out of the concrete used in construction.  This leaching process raises the pH to a value dangerous to fish.  Muratic acid is useful in lowering pH to a stabilized value of 9.0 or below.  This generally takes several days for stabilization.  Liner ponds lined with stones can also raise the pH value of the pond water, but not nearly like concrete does.  An accurate pH meter should be used to determine the pH values.  With low pH values, below 5.0, the pH can be raised by adding bicarbonate of soda (baking soda) to the water.  Once the pond pH is stabilized, it generally does not cause any further problem unless something occurs that causes a change.

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