Formal garden ponds lined with a box-welded pond liner are considered to be the best design for keeping Koi fish. An open pond with vertical sides is of particular relevance during the cold winter months when Koi migrate to the bottom depths of the pond and huddle where pond water is it’s warmest. Although this style is synonymous with keeping Koi, the design needn’t be limited to a formal one – any size in excess of 1000 gallon water capacity is suitable. 

Facts about Koi that help with good pond care

Koi fish (members of the carp family) are cold blooded creatures which means that their metabolism slows down as the surrounding water temperature drops. During cold periods they tend to move about very slowly. When the temperature drops below 50F Koi stop eating surviving the cold Winter on fat reserves stored during the warmer Spring and Summer months. They also need less oxygen as their metabolism slows.

These cold-blooded creatures go into a state of torpor – not quite full hibernation because it is for a shorter period but, it is similar with slowed metabolism, reduced breathing rate and slowed body functions. When your Koi fish are in a state of torpor your pond needs to be kept as calm and as peaceful as possible – so don’t go bashing the ice when your pond freezes over! 

Some Koi enthusiasts will argue that Koi should be housed indoors in Winter. If you consider carp in the great lakes – they survive the harshest winters of North America. Their natural metabolic process expects to go into a state of torpor and nature has ‘designed’ this period of physical and physiological inactivity for a reason – so no need to fret or feel guilty about leaving your Koi to endure the cold UK winters.

If you have kept your pond free of leaves and debris during Autumn and remove all accumulated organic matter, then pond maintenance during the cold Winter months is minimal. Your only real job is to make sure there is a surface area that remains free of a layer of ice to allow noxious gases to escape thereby preventing the pH levels of the water from being to acidic.

If you are considering becoming a Koi hobbyist, our recommendation is to build a ground-level or partly raised pond without a central island or convoluted design structure so that your Koi can take advantage of the whole of the bottom depths of the pond where the water is warmest. Box-welded pond liners create a formal look to a pond and can be ordered directly from Liners Online – all we require are your exact pond dimensions. Call us on 01526 399033 to discuss your requirements and to place an order.