How to Avoid Fish Loss During Pond Cleanouts

Spring is a happy and exciting time for pond owners. Your customers anxiously await your arrival to clean out their pond so they can start actively Living the Aquascape Lifestyle® again. You drain the pond, carefully transport the koi to a temporary location, wash the rocks, check the pump, and clean the filters. Once the dirty work is done, you refill the pond, add appropriate treatments, and carefully return the fish to their home. All looks good and the pond owner is ecstatic as they hand you the check.

A couple days pass and you get the dreaded phone call from that once happy customer. Several of their prize koi died despite your careful adherence to proper pond cleanout protocols. The news is as devastating to you as it is to the pond owner and your heart sinks. You rack your brain to determine what could have gone wrong.


Dead Koi in Pond


Scenarios like this happen to the most meticulous of pond builders, including Gary Wittstock, father of Greg Wittstock, The Pond Guy himself.

When Gary arrived at his customer’s home for a cleanout, he soon discovered several harmful issues with the neglected pond, despite assurances that had been put in place. First, a clogged biological filter blocked the normal flow of water into the pond, leading to severe and rapid water loss over the back of the waterfall filter. And because the water was escaping toward the back of the pond, the leak went undetected.

In addition, the customer had a waterfill valve on the pond which kept up with the pace of the leak. Unfortunately, the city’s water was under a temporary boil order which exponentially tainted the water in the pond. On top of all this, the Maintain treatment pouch in the Automatic Dosing System was empty and no beneficial treatments were being added to counteract the harmful levels of chlorine or chloramine.


Automatic Dosing System for Ponds


Chloramine breaks down over time and creates ammonia as a by-product. High levels of ammonia are toxic to fish. The immune systems of the koi were likely compromised before the pond cleanout even began, due to the unhealthy water conditions. A water quality test kit can be used to detect ammonia levels and Ammonia Neutralizer can be applied to the pond to quickly resolve the issue.

Protect for Ponds is another treatment to consider when fish need extra protection during times of stress or illness. Protect for Ponds is great for use after handling fish, performing pond cleanouts, or conducting water changes. This innovative water treatment uses an all-natural formulation of tea tree oil and other plant-based biopolymers to effectively protect koi and other pond fish. The special formulation helps reduce fish stress, prevents parasites and bacterial infections, and accelerates the healing of superficial wounds, scrapes, cuts, and breeding abrasions. The new Smart Pond Dosing System XT allows you to apply two different pond treatments at the same time, so you can pair Maintain for Ponds with Protect for Ponds after pond cleanouts.

In addition to the leak and untreated water, Gary found several inches of muck on the bottom of the pond. When mud at the pond’s bottom is disturbed, methane gas is created. The sulfuric acid can damage fish gills and membranes.


How to avoid fish loss during pond cleanouts


Any one of these issues alone could be enough to lead to the demise of the koi, but when compounded, it’s almost certain to result in the expiration of fish after the stress of a pond cleanout. Although devastating, the experience led Gary to alter his pond cleaning process to include the following:

  1. Instruct customer to stop feeding their fish one week in advance of the cleanout.
  2. Have customer sign off that they understand a cleanout can create stress for fish.
  3. Before performing the cleanout, assess the appearance of the fish for any issues that might weaken their immune system.
  4. Keep more of the existing pond water when performing a cleanout.
  5. When transferring fish, use a container as opposed to a net so that the fish remains in water.
  6. In addition to an aerator, use a Submersible Pond Filter in the fish holding tank.
  7. Monitor temperature of water in the pond and in the holding tank to ensure that they’re within five degrees of each other.
  8. Check expiration date of all water treatments before application.

Although you’ll likely encounter unmitigated circumstances during pond cleanouts that result in fish loss, taking these extra precautions can help lessen the occurrence of prized koi being lost.


Ebook Resources:

How to Keep Pond Water Clean and Healthy

Simple Solutions Water Treatments


Video Resources:

Aquascape Academy - starting and succeeding with water features
Automatic Dosing System for Ponds