Koi carp are a beautiful fish to keep in a pond, due to their bright colours and interesting patterns. Koi grow quite large and will just continue to grow, as opposed to other pond fish which generally grow to fit their surroundings. For this reason, it is vital that you have a large enough pond for the Koi to roam around, particularly if you have a number of fish. Koi will happily mix with other pond fish, however they do need a little more care and attention put into their surroundings. Koi will eat pond base and plants so choose either heavy duty plants or keep pond plants to a minimum. Ensure pond water is continually fresh, and if possible use a pond filter. Although Koi are fairly strong, they are inbred, which makes them slightly less sturdy than some other pond fish. Try not to feed them in too cold weather as they find this traumatic. With Japan being their country of origin, they are used to short winters but can struggle in longer periods of cold weather. Try to make the winter months as comfortable as possible by shielding the pond from strong winds or using a pond cover. Choose high quality Koi pet food and not just standard pond food. Floating sticks with high protein content are best as these promote healthy growth. Food which contains Spirulina is highly effective in maintaining the bright colours in the Koi.