For many people, a pond without fish is an impossible idea and choosing them can often be one of the most rewarding aspects of water gardening. Although there are many different varieties available, all ponds are not the same and each kind of fish has its own particular needs, so it is important to choose ones which will be suitable.
How Many Fish?
The size of the pond plays an important part in determining what kinds of fish – and how many – can be kept healthily, since some of the types commonly offered for sale can grow very large indeed. Most of pond fish require at least 50cm or so in depth, but koi and other varieties of large carp need at least double that to thrive. To get an idea of how many fish you can sensibly introduce, you need to work out the surface area – multiplying the length by the width to come up with a total in square metres (or feet). Although it is possible to increase their numbers after two or three years once the pond has become fully established, for a new water feature the total length of fish you add should not be more than around 25cm for every square metre of surface area – or 1 inch per square foot.
Garden centres and pond suppliers often stock a wonderful array of species, ranging from the familiar goldfish to some altogether more exotic kinds, such as the European Catfish – though since this grows to around two metres in length, for most ponds it is probably best avoided! Much of the decision depends on what appeals to you, but it is important to keep in mind how big your chosen fish will ultimately be and select accordingly.
Koi and Carp
Giants among pond fish, koi and other carp can grow to 75cm or more in length and so are only really suited to large, well filtered ponds, without much in the way of ornamental planting, given their habit of pulling up vegetation. Some forms of koi are highly valuable – running into thousands of pounds, so the security of your pond also needs to be borne in mind, if one of real exhibition quality takes your fancy. The common carp is also offered for sale in its various forms, including the almost scale-less “leather carp” and the large-scaled “mirror carp.” Less showy than their Japanese relation, these carp are large and impressive fish to keep if space permits. You may want to think about having a pond water heater for Koi to help them in the winter.
That old favourite, the goldfish, remains as popular a choice as ever and generally do very well. There are many varieties to choose from, though the “fancy” forms, with their bubble-eyes, enlarged heads and oversize fins are not recommended since they tend not to tolerate the cold in the winter and in the summer, faster-swimming fish out-compete them for food. More normal forms like the comets – with their long tails – and the gloriously multicoloured shubunkins are much better choices and routinely grow to 15cm or more and sometimes even double that.
Orfe and Rudd
Many pond-keepers have a particular fondness for the orfe, an active fish which spends most of its time near the surface, which makes them easily spotted – though this also means that some form of protection from cats and passing herons is probably a good idea. A gregarious species, they prefer to swim in shoals, so for them to thrive they need to be kept in groups of at least half-a-dozen, but since they can grow to 30cm or more, they need a fair bit of space. However, rudd, which only grow to about half that size, make a good alternative for the smaller pond, being very similar in their habits.
Various kinds of tench have been labelled “pond cleaners” since they spend most of their time at the bottom – in fact, you are lucky to see a tench at all after you have introduced it into the pond. The reputation is not entirely true, but their habit of rooting around for something to eat in the silt does mean that food left uneaten by the other fish is not left to rot. Some kinds of catfish, notably the European monster mentioned before, are offered for sale for the same reason, but since many of them grow to similarly impressive dimensions as their cousin, unless you are sure which sort you are buying, it is probably best to give them a miss.
Once you get your selection home, float their unopened plastic bag in the pond for half-an-hour or so, so that they gradually reach the same temperature, then open the bag and let pond water enter, to allow the fish to become accustomed to it – its chemistry will be different. After another few minutes, you can safely release them – and then all that remains is to enjoy your new arrivals.
Best fish for small ponds
Common Goldfish, Comets, and Shubunkins
These fish are all members of the carp family and are known for their hardy nature and attractive coloration. Common Goldfish are typically orange or red and can grow up to 18 inches in length. Comets have longer tails and come in a range of colours, including red, white, and orange. They can grow up to 12 inches in length. Shubunkins have a calico coloration with a mix of red, blue, black, and white scales and can grow up to 18 inches in length.
All three of these fish species are active swimmers and can provide a lot of movement and interest in a small pond. They are also relatively easy to care for and can tolerate a range of water conditions. However, it’s important to note that they can grow quite large, so a larger pond or adequate filtration may be necessary as they mature.
Minnows and Sticklebacks
Minnows and Sticklebacks are smaller fish that are well-suited to smaller ponds. Minnows are typically silver or gold in colour and are active swimmers. Sticklebacks are known for their spiny armour and can help control insect populations in the pond. Both species are hardy and easy to care for, and can be a good choice for those new to keeping fish.
Mosquito Fish are small, freshwater fish that are known for their ability to eat mosquito larvae. They are hardy and can tolerate a range of water conditions, making them a popular choice for small ponds. However, it’s important to note that they can breed rapidly, so it’s important to monitor their population and ensure that they do not become overpopulated.
Red Shiners are a colourful fish that can add interest and variety to a small pond. They are known for their bright red coloration and can grow up to 3 inches in length. They are hardy and can tolerate a range of water conditions, but they do require a higher protein diet than some of the other species mentioned here. It’s also important to note that they can be slightly more aggressive than some other small pond fish, so they may not be the best choice for a community pond.
Fish for UK ponds, for large and small ponds
Goldfish are freshwater fish and members of the carp family. They are native to East Asia and were first domesticated in China over a thousand years ago. Goldfish come in a variety of colors and patterns, and are a popular fish for aquariums and outdoor ponds.
Shubunkin are a type of goldfish that were developed in Japan in the early 1900s. They have a calico coloration with a mix of red, blue, black, and white scales. Shubunkin are hardy fish that can tolerate a wide range of water temperatures and are popular for outdoor ponds.
Sarasa Comet, also known as Comet goldfish, are a type of single-tailed goldfish. They have a long, streamlined body and come in a range of colors, including red, orange, and white. Sarasa Comet are hardy fish and are popular for outdoor ponds due to their ability to tolerate a range of water conditions.
Comet goldfish, also known as Comet-tailed goldfish, are a popular type of goldfish with a long, slender body and a single tail. They come in a variety of colors, including red, orange, and white. Comet goldfish are hardy fish and are a good choice for outdoor ponds.
Koi carp are ornamental fish that are a member of the carp family. They originated in Japan and are known for their beautiful patterns and colors. Koi come in a variety of colors, including red, orange, yellow, and white. They are popular for outdoor ponds and can live for several decades.
Ghost koi, also known as Butterfly koi, are a hybrid fish that are a cross between koi and wild carp. They have long, flowing fins and come in a variety of colors, including white, black, and orange. Ghost koi are hardy fish that are popular for outdoor ponds.
Common carp are a species of freshwater fish that are found in Europe and Asia. They have a long, cylindrical body and can grow quite large. Common carp are popular for fishing and are also used in aquaculture.
Mirror carp are a type of common carp that have large, mirror-like scales. They are popular for fishing and are also used in aquaculture.
Golden Orfe are a type of freshwater fish that are native to Europe. They have a slender body and come in a range of colors, including gold, silver, and blue. Golden Orfe are popular for outdoor ponds due to their hardy nature and active swimming style.
Blue Orfe are a type of Orfe that have a blue coloration. They are popular for outdoor ponds and can tolerate a wide range of water conditions.
Green Tench are a species of freshwater fish that are native to Europe and Asia. They have a dark green coloration and are popular for outdoor ponds due to their hardy nature.
Golden Tench are a type of Tench that have a golden coloration. They are popular for outdoor ponds and can tolerate a range of water conditions.
Rudd are a freshwater fish that are native to Europe and western Asia. They have a silvery coloration and are popular for fishing.
Golden Rudd are a type of Rudd that have a golden coloration. They are popular for fishing and are also used in aquaculture.
Roach are a species of freshwater fish that are found throughout Europe and Asia. They have a silver coloration and are popular for fishing.
Barbel are a species of freshwater fish that are found in Europe and Asia. They have a long, cylindrical body and are popular for fishing.
Gudgeon are a small species of freshwater fish that are found in Europe and Asia. They are popular for fishing and are also used as bait.
Stickleback is a family of small, freshwater fish that are found in temperate and cold regions of the Northern Hemisphere. They are known for their distinctive spiny armor and are popular aquarium fish. Some species of stickleback are also used in scientific research as a model organism to study genetics and evolutionary biology.
Grass carp, also known as white amur, is a species of freshwater fish that is native to eastern Asia. They are herbivorous and are often used in aquaculture to control the growth of aquatic plants. Grass carp are also popular for fishing and are prized for their size and fighting ability.
Sturgeon is a family of large, primitive fish that are found in temperate regions of the Northern Hemisphere. They are known for their distinctive long snouts and rows of bony plates called scutes. Some species of sturgeon, such as the beluga sturgeon, are prized for their caviar, which is considered a delicacy.
Sterlet is a species of small sturgeon that is native to Eurasia. They have a distinctive elongated body and rows of bony scutes along their sides. Sterlet are popular for aquaculture and are also prized for their meat, which is considered a delicacy in some regions.
Bream is a family of freshwater fish that are found throughout Europe and Asia. They have a deep, flattened body and are known for their large, round scales. Bream are popular for fishing and are prized for their size and flavor. Some species of bream, such as the common bream, are also used in aquaculture.