Winter Water

Buying fish in Winter – Good or Bad?

Winter is often seen as a time that the pond is left to do it’s own thing. The plants die back and the fish not as active as in the warmer months. So is the winter a good or bad time to introduce fish? Well lets look at this and some other winter routines we need to carry out as well as should we stock?

Pond Maintenance

The pond still requires maintenance throughout the winter. Filters need to be kept clean, all be it on a less frequent interval as the fish consume less and produce less waste. But it is critical that water parameters are measured and kept in check as required. You are going to have to get some cold hands! 


There are a number of myths around feeding. Some insist that only wheatgerm be fed as the fish cannot process protein, others simply believe fish hibernate over the winter. Both are not necessarily true. Certain fish species, such as Koi,  may enter a state or torpor in cold extremities, others simply carry on about their daily business such as Sturgeon. It’s important to understand the requirements of the different fish types you may own (see our Fish Facts for more info). A good quality food appropriate for the fish type you own should be fed if the fish are feeding. Consider both Koi and Orfe have natural counterparts in the wild in the UK, Carp and Ide, both readily seek protein rich food in the winter to provide sustenance. Wheatgerm will provide a low protein diet and some food value, we recommended a more balanced year round feed. Any food not absorbed will simply pass through the fish (not cause them to rot from the inside like some old wives tale!). 

Feeding should certainly be a fraction of the summer amounts, but should be carried out over the milder periods. You don’t want a starved fish coming into the spring, trying to kick start it’s metabolism. 

Winter Stocking – Good or Bad?

Well we sell a selection of fish year round for ponds. We generally only stock limited sizes and do tend to stop selling Koi over the winter (we have found they struggle in the tanks over winter due to the above ground set up and decreased temperatures associated with this). 

We also stock a number of winter species such as Trout and Graying that otherwise wouldn’t be shippable during the summer months due to their oxygen and temperature requirements. 

There seems to be an industry led rule that states that stocking your pond over the winter is a bad thing. Quite possibly led by garden centres that have their pond fish over the summer months and shut their aquatics down in the winter. But quite the opposite is true in the restocking and fishery industry. Our native fish species are mainly moved in the months of November to March, most when waters are at their coldest. This is down to a couple of factors:

  • Oxygen saturation is at it’s highest in colder water temperatures. This allows more fish to be moved in less water and there is less likelihood of temperature fluctuations and oxygen crashes
  • Most fish species are less active, therefore less likely to become injured or damaged during capture, handling and shipping

So purchasing pond fish in the winter is not an issue, but there are more factors to consider other than the above.

The fish need to be coming from outside temperatures. Some retailers may house pond fish indoors where there could be a significant difference in temperature. Rapidly reducing the temperature of fish from say 15°c to 5°c is not going to do the fish any good. In fact, it will severely and rapidly suppress the immune system and possibly cause a rapid death. Ask the retailer for a temperature or where the fish are housed before ordering. All of our pond fish are kept outside year round. 

Consider the activity of your new fish in winter. They are likely to be a lot slower and not be feeding as regularly. This is normal behavior in the winter. Smaller fish may well find a place to hide until the better weather. 

Avoid the temptation to ‘grow on’ in an aquarium. We have had calls from inexperienced fish keepers who have received fish and then put them in an indoor aquarium to grow on. The fish can then struggle and can develop issues. When we re-iterate that they are pond fish, the customer says ‘well i left the bag in the tank for 20 minutes to acclimatise!’ 

Consider that the temperature has potentially gone from 5°c to 18°c in 20 minutes! The fishes immune system will not kick in that quickly, there will be a significant and rapid change in dissolved oxygen content and we are expecting the poor fish to become acclimatised to this in 20 minutes! If you are considering fish for growing on in an aquarium, contact us first as we do keep a select few fish at warmer temperatures for this purpose. 

The decision to buy is down to you, there is no reason you cannot purchase fish year round. The spring, summer and autumn months will certainly offer a greater selection of fish, but the winter is really not a problem for stocking your pond should you wish. As long as you follow the guidance!