Choosing Fish and Plants for a Garden Pond

I've linked these two topics because without fish and plants, your pond is no more than a hole filled with water. The movement and colour of the fish bring the pond to life and carefully selected plants can provide year round interest as well as contributing to the overall health of the pond and hence your fish.

Fish        Plants        Deep-water Plants        Oxygenators       
Lilies        Others        Shallow-water Plants        Edging Plants       


Fish

The type of fish that you can keep in your pond will be dependent upon how you have built it, and the type of filtration that you have installed. The biggest and most exotic fish are Koi. Given the correct conditions, these fish can grow to almost 1m in length. However, as I've mentioned on other pages in my site, if you want to have the really big fish, they require specialist filtration systems and pond heaters and will need a much deeper pond than other fish. Having said that, I have a number of "ghost Koi" in my pond and a silver ogon and I just have a normal filter that I built myself. The ghost Koi are pale brown with brass coloured scales along their back. Not as brightly coloured as the rest of the varieties but they mix well with the rest of my fish.

In virtually all "natural" garden ponds like mine you will find a variety of types of fish. Even those people who have only one species will usually have more than one variant. A mixture of goldfish, shubunkins, comets and orfe provides colour, movement and variety of shape, activity levels and preferred location within the pond. Watching the constant movement and mixing of the colour and shape is extremely relaxing and helps to contribute to the feeling of tranquility within the garden.

Before choosing your fish, visit a number of different water garden centres and see the variety of fish that are available. Take care to be critical when looking at fish. You don't want to introduce a damaged or diseased fish into your pond. As you'll see, the price of the fish varies considerably and of course, the bigger the fish, the more they cost. Very large Koi can cost many 1000. I wouldn't advise spending a great deal on fish for a new pond for a couple of reasons. Firstly, it takes time for the water in the pond to achieve its natural balance as plants and filtration systems get established and it is possible to lose fish during that time. Secondly, unless you want to create an immediate impact, you don't have to spend a lot. In a healthy pond, fish grow at a tremendous rate for the first few years.

I would advise buying a few reasonably sized fish (for goldfish etc about 12 - 15 cm) for which you can expect to pay about 5 each and then buy as many others as you want, as small as they come. You can often get 5 cm goldfish at 10 for 10. Within a year they will almost double in size and again the following year. In this way, you will have a few to look at this year and by the following year, your pond will look really good. However, if it all goes horribly wrong and you lose your fish, you won't have lost too much. I bought one of my ghost koi and my silver ogon as a 5cm fish 9 years ago and they are now over 45 cm long. It would cost close to 400 to replace the silver ogon with a fish of similar size from a water garden centre. And I've had the pleasure of watching them grow, knowing that I was providing the right conditions to keep them healthy.

When you are sure that your pond is in good condition, and see my Maintenance page for advice, a good tip is to try and find out when your water garden centre stops selling fish for the season. Few of them have the conditions or the need to keep fish through the winter, so they usually stop selling fish by late September each year. That is often a time for really good bargains. You will often be able to find fish at less than half their usual price. A caution here though. It can take a fish a little time to settle down in a new environment and until that time, its stress levels will be high. At the end of the summer, as the water gets colder, the fish become less active and less able to fight off any illness so if you leave it too late to get your fish, you could lose them. I've always taken the gamble, and I might simply have been lucky but by doing this I have saved a lot of money.

Another way to increase your stock is to get to know people who have a well established pond. Its likely that their fish will produce too many young for the pond to cope with, and many people are only too happy to help others start up. Also check your local advertising paper. Some people don't like ponds but find that they inherit one when they move house and simply want the fish removed without them being hurt or killed. I've known friends to acquire really big fish in that way. Another caution though. Check that the other pond is healthy and always try to quarantine the new fish so that you can ensure that they are OK before risking introducing diseases into your pond. And of course, if your fish and pond are healthy, your fish will breed and your stock will increase at zero cost to you.  Top



Plants

I have divided the plants into three sections. Those that live in the deeper parts of the pond, those that live in the shallow areas and those that live outside the pond but are great for edging the pond and covering the liner.

Deep-water Plants

This section comprises two major types - oxygenators and lilies - although there are a number of other deep water plants to consider.  Top

Oxygenators

For fish, like us, oxygen is vital for life. It is present naturally in water and in the wild, where the balance between fish and plants is achieved through natural balance and selection, no other help is needed. However, as mentioned on other pages, no matter how hard we try, the average garden pond is not a natural environment. Invariably we have more fish and bigger fish than a similar sized pond in the wild could support. Therefore, we need to assist with the oxygen supply. Waterfalls are good for this as they aerate the water and help to increase the oxygen level. But we also need to add some specialist plants which give off oxygen into the water. There are a large number of types and they all have different growing habits. You need to find the right one for your pond.

Oxygenating plants usually do not need to be potted up like lilies since they have roots throughout their length and take all their nutrient from the water. However, I have always planted then so that they are anchored and therefore remain in one area of the pond. As well as providing oxygen, these plants remove harmful nutrients from the water and provide the perfect environment for other pond life. They are also ideal for the fish to spawn in and, as fish are carnivores, they provide shelter and protection for the fry until they get bigger than bite-sized.

Water garden centres will usually sell these plants wrapped in a small piece of lead substitute so that they sink to the bottom of the pond. Once again, don't forget your friends. Once this stuff get properly established in a pond, it soon grows out of control if not regularly pruned. Check to see if your friends are about to throw any onto the compost bin. It would be better off in your pond.  Top

Lilies

The lily is a fabulous plant for the garden pond because it requires so little maintenance and yet does so much for us. Lying dormant through the winter, the lily welcomes the spring with the first of a series of small leaves which seem to serve as depth finders. Once they reach the surface, the plant begins a continual succession of leaves and flowers that last well into the autumn. The leaves spread out to provide shade for the fish from the fierce rays of the summer sun and as they prevent the sun from penetrating the water, they significantly reduce the amount of algae growth, so reducing the amount of work required by your filter to keep your water clear.

There is a huge variety of lilies from which to chose and you need to take a bit of care over your choice. The prettiest one may not be the best for your pond. Lilies come in all sorts of sizes and require different depths of water. The ideal is to have the lily cover about half of the pond so that it provides protection but still enables you to see your fish. All good water garden centres will be able to tell you the names of their lilies so you can check in the reference books to see the growing habits of any particular plant.

Once again, don't forget your friends. Lilies need to be thinned out every few years. If you know someone who has a plant that you admire and you can see that its growth habit would suit your pond, ask for a cutting. Most people love to swap plants and you can always repay the favour at another time.

Once you get your cutting, you need a suitable container. Its best to get a specialist basket from the water garden centre. These resemble flower post made of plastic mesh. The basket should be lined with hessian or man-made mesh so that the lining is proud of the basket by about half the diameter of the basket and filled with lily compost or normal garden earth. The lining is needed to stop the earth leeching into the pond. DON'T use normal compost. It is far too nutritious for the plants and the additional nutrients will harm the balance of your pond. Fill the basket to about 5 cm from the top and plant the cutting as for any other plant. Then fold the remaining lining over the top of the earth and cover it with small pebbles. Covering the basket in that way should prevent your fish from digging around in the pot and disturbing the earth and clouding your pond water. Koi are particularly keen on that and will rip out any plants that they can get at. That's one of the reason for specialist Koi ponds being devoid of plants. However, I haven't had a problem with mine and that may be because they live in a mixed pond and feed along with all the rest of my fish.  Top

Others

There are a number of other deep water aquatics and most of them produce flowers, though not as big or bright as the lilies. My favourite of these is the water hawthorn. It has an small oval leaf and lovely scented white flowers which have black anthers and are borne on stalks that float on the surface. The great advantage of these is that they start to grow just as the lilies are dying back and they provide interest through to the spring. Ideally, the tubers should be protected from frost by planting them fairly deep, but I have found that they grow well with their roots planted between the rocks at the edge of my pond. For other examples, you will need to consult a good reference book.  Top

Shallow-water Plants

There is a bewildering variety of plants for the shallower areas of the pond. Known as marginals, they offer many different shapes, sizes and colours. The plants will all survive in shallow water, but to really thrive, they need to be at just the right level for their needs. eg some like to be completely submerged, whilst others need only to have their roots in the water whilst their stems are completely above water. Personal choice is the key but if you want somewhere to start, check my ponds. I've got Iris, Marsh Marigold, Mimulus, Houttunynia, Water Forget-me-not and some grasses.

These plants tend to be dormant through the winter and a few may need some protection from frost, but in the summer they provide continual shows of flower. Easy to propagate, simply pull out a handful and plant it elsewhere. You don't need to take much care as they are all reasonably invasive and its usually more difficult to control them than to get them to grow. Indeed, some of them need to be kept in containers so that they don't take over the pond. Follow the instructions on the label.

As you will see from my construction pages, I often wedge small pieces of the roots of these plants in between the rocks surrounding my ponds when I build them. In that way, their roots have a firm anchor to stop them being dragged out by the fish and the plant begins to grow within only a couple of days. It also means that the roots are offered some protection from ice in the winter. You need to be careful to ensure that if you plant anything in this way that the plant does not get too tall for the first year. The roots won't have had a chance to wrap themselves around the rocks during the first year or so and there is a danger that the plant could topple into the pond.

As I have mentioned, these plants can grow very quickly. The red flowered plant next to the waterfall in the top, left picture on my home page is a mimulus. If I'm not careful it will grow across the waterfall and block the path for the water. I lost a lot of water one weekend because we were away and I had not monitored its progress closely enough. The problem is that when these plants are in full flower, there is nothing more showy in the garden, so the tendency is always to let them spread as far as possible to increase the effect. When its time to cut back, simply hold the plant at the limit you chose and rip away anything left. The plant must be held in this way because they are quite delicate and you could easily pull out half of your root stock. You can also use shears, but do be careful of the liner.  Top

Edging Plants

The edge of the pond provides a unique environment within the garden. The proximity of the water usually means that the foliage of the plants at the edge of the pond is particularly healthy. For that reason, you will often find hostas and other broad leaved plants flourishing. I have also used pulmonaria, ladies mantle, heuchera, cerastium and polygonium as well as some small trees. I've been careful to select plants that are happy living together and spreading into each other, but are not going to require too much maintenance and I'm really pleased with the overall effect.  Top