Koi Pond Leaks. How to Find a Fish Pond Leak

Page Summary: Here's my view on heating ponds over winter. Completely unnecessary. That doesn't mean to say koi keepers don't do it because they do. However unless you are into the serious showing of koi or have enough money to want to enjoy seeing your koi swimming happily around the pond the whole year then literally heating pond water during cold winter months is a waste of money. The point has been made in other articles that Koi will quite naturally start to think of hibernating when temperatures of pond water reach about 8 degrees C or so and continue falling.

Ponds Don't Freeze Solid

The point is also made that it is only under extreme and prolonged freezing weather is there any chance of an outdoor pond freezing completely.

I can't think any pond of 4 feet or more depth will ever freeze solid except in the most extreme climates and koi tend not to be kept in these climates anyway

The reason why ponds do not completely freeze even under harsh conditions is that water has a maximum density at 4 degrees C. This means ice forms from top of pond down and the lower layer (at 4 degrees) cannot freeze.

It is because of this critical and almost unique property of water that the the earth has survived the ice ages. It's why you and I are here, able to enjoy pondkeeping.

Koi Pond Care: Spring Pond Care Considerations:

As a first point I am not in conditions. It is a fact of life that the vast majority of koi keepers will do more harm than good once the never-ending process of adding powerful chemicals to pond water starts.

Adding the more environmentally friendly and biological components such as pond starters and Viresco is however a good option as water warms up. Whatever can be done to increase the chances of a successful Winter to Spring transition happening is a good thing. You can also be pretty sure that online koi pond product retailers will start to offer good deals on koi food as spring approaches and so long as food is high quality and well packaged (an airtight container is mandatory even if you buy the koi food in a bag).

Koi immune systems have inevitably been weakened over winter and this why ensuring the biofilter starts working efficiently and quickly as water warms up.

Almost all lifeforms re-energize as air or water temperatures increase and koi or goldfish are no different. The urge to start life afresh is there for all living creatures and organisms. Some start to spring to life earlier than others after a prologed rest over the winter months in the koi pond

If you didn't clean out your biofilter before winter then now is the time to empty it, get rid of any sludge build up and get it ship shape for the upcoming season. Always use pond water to clean filters, sponges, biomedia and whatever else you feel the need to clean.

Reduce the urge to pump pond water out of the koi pond so you can refill it with "clean water". This will do considerable harm to the aquatic environment which has reached a degree of stability. Great ponds and good pond keeping rely upon stable pond environments

If you have for whatever reason emptied the filter over winter then you need to get it working again long before the warm weather arrives. Pond starters can be helpful in this regard.

Keep a careful eye of fish behaviour

What you're looking for is any sign of abnormal koi behaviour in one or more fish.
Inspect fish as carefully as possible. Especially look out for ulcer formation since the stressful overwintering conditions can make koi more prone to bacterial, ulcer (aeromonas) infections. Close inspection of fish can be carried out using specially design "flattish" pond nets that can be used to gently scoop koi and bring them to the pond edge for close inspection. Avoid removing the fish from the water unless absolutely necessary. In particular check for fin damage, sores, lesions and parasites such as lice and flukes.
Make sure koi or goldfish fins have not been damaged and that the fins look and behave normally.