What Types of Fish can you keep Outdoors in a Garden pond

Pond Fish

A well-designed pond makes an impressive addition to any garden but lets be honest it’s the fish that bring it to life.

Choosing the right fish to add to your pond is not as simple as dumping some in and hoping for the best, there are a few things you need to consider.

The size of the pond and the local climate can have an impact on whether your chosen fish will not only survive but thrive for years to come.

The amount of fish and the variety of fish also plays a big part in keeping fish in an outdoor pond.

How big your fish will grow and how deep your pond is also has to be taken into consideration.

Goldfish for your garden pond.

The good old goldfish is the staple of many aquariums, they are very hardy and undemanding, but best of all many are perfect for a garden pond.

Perfect for beginners and experts alike, these glorious fish can grow quite big when taken out of the confined space of a goldfish bowl and placed in a garden pond, it’s not unusual for goldfish to exceed 30cm (12″) long.

Because they can grow that big they need a pond that is big enough to provide ample space for them to swim around and a good filtration system to keep them healthy.

The minimum sized pond we would suggest to keep goldfish in is about 1100 litres (250 gallons) but the bigger the better and as a rule of thumb 225 litres of water (50 gallons) per fish with a depth of at least 60cm (24″) which should account for at least a third of the area of your pond.

Types of Goldfish suitable or not so suitable for a garden pond.

  • Common Goldfish: These have elongated flat body that tapers towards its tail fin. The most distinguished colour is bright orange, but they also come in various solid colours and combinations of white, yellow, orange, red, brown and black. They can grow over 30cm (12″) and have a lifespan of 10-15 years. A peaceful but active fish and one of the hardiest of the goldfish varieties.
  • Comets: Theses were developed from the common goldfish, they have a long slender body with longer forked tail and are more reddish orange in colour, but also available in yellow, orange, red and white. They have a lifespan of 4-14 years and can grow up to 30cm (12″). Active which might annoy pond mates and very hardy.
  • Sarasa Comet: These are the same as the Comet but with deep red and pure white coloration.
  • Fantails: These have a short round body with twin tails and are mainly orange or yellow but can be speckled or matt, which is a whitish color. They grow up to 20cm (8″) and have a lifespan of 10-15 years. Docile, very hardy and good scavengers.
  • Shubunkins: These have very similar body shape to the comet with the main difference being the variety of their colour patterns that are almost always speckled or have a variegated colour pattern. There are two types of Shubunkins, the London and the Bristol. As they get older their colour might change. They have a lifespan of 10-15 years and can grow to an impressive 40cm (14″). Playful, athletic and very hardy.
  • Black moor: These look like black fantails but with a distinguishing feature, their bulging eyes that protrude from either side of its head. As the name suggests these fish are black but can fade to grey as they age. They have a 5-10 year lifespan and can grow up to 20cm (8″). Docile, clumsy with poor eyesight but relatively hardy.
  • Bubble eye: As the name suggests these fish have what looks like bubbles for eyes with the body of a fantail. Colours include solids of red, blue, chocolate and black and bi-colors of red/white and red/black. They have a lifespan of 15-20 years and can reach 15cm (6″). Not very hardy so we would not recommend them for an outdoor pond.
  • Pearlscale: Another fish that is shaped like the Fintail with a short stubby body but with twin tails. Colours can range from red, blue, black, calico, chocolate, and red/white combinations. They have a lifespan of 10-15 years and can grow up to 15cm (6″). Good natured and very hardy.
  • Ryukins: Similar to the shape of a Fantail but with a a different slope to it’s back making it as tall as it long. Common colours being solid reds and reds and whites but also in tri-color, calico, white, and chocolate. They can reach 20cm (8″) long and be just as tall with a lifespan of 10-15 years. Very hardy but can be a bit aggressive.
  • Ranchu: These are more rounded or egg shaped than the common goldfish and closely resemble the Lionheart. They come in a variety of colours but most common is the bi-colours like gold and white and red and white. They have a life span of 10-15 years and grow to about 13cm (5″). Good natured but a bit delicate and less hardy.
  • Lionhead: These fish are unlike common slender goldfish as they have a more rounded egg shaped body with a double tail. Their most distinctive feature is the hood on the head. Available in a variety of colours, including red, orange, chocolate, blue and black. They can also be calico, bi-colored in red and white or red and black, or tri-colored in red, white, and black. They have a lifespan of 10-15 years and can grow up to 13cm (5″). They are a delicate fish but very peaceful.
  • Celestial Eye: Another eggs shaped fish with very distinctive eyes, they extrude from the side of the head and look upwards. Colours are orange, black, and a pretty calico. They can grow up to 13cm (5″) and have a lifespan of 10-15 years. A docile fish but not very hardy.
  • Oranda: This could be the most popular goldfish in the world. It’s another egg shaped fish but it’s favoured for it’s hood that grows on the top of its head. They have matt and metallic scales in various colours including red, black, calico, chocolate, blue and red/white combinations. With a lifespan of 5-10 years they can grow 18cm (7″). Not the hardiest of fish but very gentle.
  • Redcap Oranda: The redcap is the same as the Oranda above but is has white shimmering scales with a red hood.
  • Telescope: This is very similar to the Fantail with a short egg shaped body but the most curious characteristic is their large eyes set on top of long telescope stalks mounted on the sides of its head. Scales are metallic or nacreous, but seldom matt. Colours include solid red, blue white or chocolate, bi-coloured red/white and black/white plus tri colours. They can grow up to 30cm (8″) and have a lifespan of 10-15 years. A peaceful fish, hardy but because of there eyes they are prone to problems.
  • Veiltail: Their body is stubby and their head is wide similar to the Fantail but its body is rounder and a long tail. Colours include solid orange or red, variegated colours and calico. They have a lifespan of 10-15 years and can reach 18cm (7″) with their tale taking up about half that length. Because of their fins they are a delicate fish to keep but relatively docile and easy-going.

When choosing Goldfish for a garden pond you need to take a few things into account.

The hardiest fish to have in your garden pond are the common goldfish, comet goldfish, fantail goldfish and shubunkins. These are great for beginners and a relatively cheap to buy.

The egg shaped “fancy goldfish” are less hardy so will need a bit more care, also they are slow swimmers so can’t compete with the slender common type of goldfish when it comes to feeding so you should not mix the two.

“Fancy goldfish” with bulging eyes can suffer with poor eyesite and their eyes can easily be damaged.

Koi for your garden pond.

Koi carp (Nishikigoi) are probably the most popular fish along with goldfish that people associate with garden ponds but Koi can be harder to keep than goldfish.

It’s easy to distinguish between the two of them because Koi have two pairs of barbels on the upper lip and the goldfish doesn’t have any.

If you would like to keep Koi there are a few things you need take into account.

Koi need a pond of a least 4500 litres (1000 gallons) of water with a large surface area and a depth of at least 1200cm (4ft) in places to really survive, be healthy and happy, the depth should be at least a third of the area of your pond.

Koi can grow up to 1 metre (39″) in length and can quickly outgrow a pond so build the largest pond that you possibly can, the larger the pond, the easier it will be to maintain.

The filtration system needs to be a lot better than a pond that holds just goldfish as Koi produce a lot more waste (poo) which needs to be filtered, a larger pond will help to dilute the ammonia that comes from Koi waste so keep that in mind.

Koi eat plants so having ornamental plants like water lilies are a no no but there are a few select plants that can used.

Unlike goldfish which have been bred over the years to give various forms of fins, bodies and eyes the Koi breeders have kept the same form and concentrated on different scales, colours and patterns.

There are hundreds of different Koi to choose from.

The 13 classes of Koi.

  • Kohaku: This is one of the most highly prized of the Koi varieties. It has a non-metallic white body with a red pattern on its back.
  • Sanke: Another non-metallic fish with a red and black pattern on a white base, the black along it’s back should be in small patches.
  • Showa: These are often confused with the Sanke above but this one has red and white markings on a non-metallic black base.
  • Utsurimono: This is a bi-colour fish with a black base, the second colour can be red, yellow or white.
  • Bekko: This Koi has a black pattern on a base that can be red, yellow or black.
  • Asagi and Shusui: Asagi is one of the oldest form of Koi and has a blue back with red flanks under the lateral line and red cheeks just under the eyes. The blue scales look like a net because they are edged with white. Shusui is a scaleless version of the Asagi and there are several sub varieties of both.
  • Koromo: This Koi is made up from Kohaku, Showa or Sanke and has a bluish or blackish overlay on a red pattern.
  • Kawarimono: This is the last of the non-metallic class of Koi that do not fall into any of the earlier groups which include Goshiki (5 colours) Hajiro, Midorigoi and Chagoi.
  • Ogon (Hikarimuji): This is a one coloured metallic Koi which is traditionally gold but can be found in several colour variations.
  • Hikarimoyo: A metallic Koi with two or more colours, this class includes Yamatonishiki, Kujaku and HYaiwake.
  • Hikariutsuri: This is a class for metallic Utsun and Showa varieties such as Kin Ki Utsun and Kin Showa.
  • KinGinRin: Showa, Kohaku and Sanke are highly reflective scales rather than the metallic gold or silver scales.
  • Tacho: A Showa, Kohaku or Sanke that has a well-placed red mark on its head.

Other garden pond fish to consider.

The majority of fish that are kept in garden ponds are highly coloured for obvious reasons, these are carefully cultivated domestic strains that the pond keeper loves, but there are other fish that do well in ponds.

Golden Orfe.

The Golden Orfe is very lively fish that can provide a lot of interst in your pond, a very shy fish on it’s own or as a couple but comes to life when it’s in a shoal.

It’s a hardy fish that’s long and slender, reaching 30cm (12″) in length with a pale golden colour that fades to silver.

It likes a large pond where it can swim without restrictions and is a great scavenger removing insects and mosquito larvae from the water surface and plants.

During winter, it likes to lie dormant near the bottom of the pond.

Golden Rudd.

The scales on the Golden Rudd are large, rough and distinctive, but it’s a very attractive fish that has a silvery colour with a golden hue.

Their fins are red as are their eyes, while their anal, pelvic and pectoral fins are darker, they are often mistaken for the Roach.

They can grow up to 45cm (18″) in length, can weigh up to 2Kg and feeds on aquatic vegetation, ant eggs and worms.

Very similar to the Golden Orfe but not as bright in colour.

Very hardy and will live happily with other fish.

Golden Trench.

The Golden Trench is a very hardy fish and can live out of water for quite a long time.

It prefers still water to running water where it grows well and should have two males to every female were they will quikly increase if the conditions are right.

They have a slimy skin which is reputed to cure various deceases on other fish in your pond.

Dark green in colour with very dark green fins and pink lips, they can grow up to 45cm (18″) in length and can weigh as much as 2.5Kg.

Their natural food is young shoots from vegetation, worms and insects, they are great scavengers as they love to feed of the bottom of your pond.


These are small fish 7.5cm (3″) that prefer to live shoals which gives plenty of movement in a garden pond.

They can live a long time, up to 12 years and can change colour according to their surroundings , going from light to dark.

A hardy breed that lives on flies, worms and meat, they are bold enough to take food from much larger fish.

Grass Carp.

Although the Grass Carp looks like it would be a perfect fish to help keep down the algae growth in your pond they do have a very healthy appetite and will eat your oxygenating plants as well.

They can grow over 90cm (36″) in length, so we don’t think these would make a good pond fish.


The Catfish has a reputation of being a good scavenger, they patrol the bottom of your pond cleaning up all the leftovers, sounds good but introducing them to a garden pond is not something I would not recommend.