The enduring popularity of koi and goldfish is fairly well evidenced. They have been cultivated commercially for centuries. Countless distinct varieties of these fishes have been developed. They account for an appreciable share of the ornamental fish industry (according to recent USDA findings, sales from U.S. koi and goldfish farms exceed $10 million annually). And, arguably, they are the consummate pond fishes, coming in a multitude of forms and colors while exhibiting an undeniably endearing personality. Indeed, they are so superbly suited to the modern ornamental pond that few pondkeepers ever consider keeping anything else.
A pond doesn’t have to be filled with just koi or goldfish. There are other interesting fish that you can add.
All of that notwithstanding, there are some very practical, if not rewarding, alternative fish species available for all kinds of water gardens. There are certainly some good reasons to opt for these alternatives. For one, particularly among those who maintain smallish container gardens, it may be more feasible to keep petite types of fish. Some may prefer to keep species that can better evade predators such as herons or raccoons. Some others may wish to restore or rehabilitate a disturbed natural area with the use of native species. In many cases, some simply want something a little bit unusual.
With particular respect to husbandry, not all pond fish are the same. These animals originate from many different types of habitats from all over the world, and consequently have different needs in captivity. While most are reasonably tough, some will only survive under certain conditions. Therefore, it is important to research the specific care requirements of each candidate species before acquisition. Among other things, pondkeepers should consider temperature tolerance (both high and low), ideal water chemistry, preferred depth and surface area, preferred substrate type, special shade or shelter requirements, diet and susceptibility to disease, as well as compatibility with other candidates.
Goldfish have been kept for centuries.
Regardless of ones needs, there is a surprisingly broad selection of fishes that may be acquired for pond stocking. These sources will most typically be aquarium shops, mail order hatcheries, bait shops and (where permitted by law) the natural environment. Whatever the source may be, it is highly recommended to check with suppliers as well as the appropriate local authorities to ensure that the prospective species are both suitable and legal for use in the area.
Here below we provide a mere sampling of (sort of) commonly kept pond fishes, ordered on the basis of minimum pond size. While hardly an exhaustive list, it does provide examples of species that can be used by pondkeepers in a variety of situations.
Prospective Pond Fish Species
Three-spine stickleback (Gasterosteus aculeatus)
This is a busy, oftentimes feisty little fish (just 2 inches (5 cm)) that feeds at all levels of the pond. It tolerates a wide range of salinities. It favors thick emergent vegetation. Males of the species are more brightly pigmented, particularly during courting. Sticklebacks exhibit complicated breeding behaviors that include nest building and guarding of eggs. Ideal temperature is 68°F (20°C). Ideal pH is 8. It should be kept in ponds over 13 gallons (50 L).
Yellowfin shiner (Notropis lutipinnis)
Not as active nor as large ((2.5 inches (7 cm)) as the golden shiner, this species doesn’t require nearly as much space. However, it does prefer the company of its own kind. It is a planktivore and benefits from the presence of daphnia, insect larvae, etc. Provide moderate water movement and a sand or gravel bottom. Ideal temperature is 68°F (20°C). Ideal pH is 7. It should be kept in ponds over 18 gallons (70 L).
Amur Bitterling (Rhodeus sericeus)
This bottom feeder is most impressive when kept in small shoals. It reaches a length of 2-3 1/2 inches (5-9 cm). Bitterlings are known for a rather unusual breeding behavior; ripe females use an extended ovipositor to deposit eggs into the mantle cavity of freshwater mussels. Ideal temperature is 64°F (18°C). Ideal pH is 6.8. It should be kept in ponds over 19 gallons (75 L).
Common loach (Noemacheilus barbatus)
This social bottom feeder should be kept in groups. Provide areas with high water movement and a gravelly substrate. It reaches 6 inches (14 cm) in length. It spawns directly onto gravel and stones between March and May; males may be observed guarding nesting sites. Ideal temperature is 64°F (18°C). Ideal pH is 7.8. It should be kept in ponds over 19 gallons (75 L).
Weather loach (Misgurnus anguillicaudatus)
A golden yellow form is available in the aquarium trade. Being that its activity level changes with changes in atmospheric pressure, this fish has been used (with unproven accuracy) to forecast weather. It is valued by both aquarists and pond enthusiasts as an exceptionally hardy species. It is a shy and reclusive animal that benefits from an abundance of sheltered areas. When suddenly alarmed, it may dive into the pond bed. Provide a fine sand or mud substrate as well as vegetation and rockwork to hide in. It reaches 8 inches (20 cm) in length. Ideal temperature is 64°F (18°C). Ideal pH is 6.7. It should be kept in ponds over 19 gallons (75 L).
Rosey red minnow (Pimephales promelas)
Where this is a pretty little shoaling fish ((just 3 inches (7.5 cm)) ) is given plenty of living space, it is very hardy. While it easily tolerates winter conditions, the ideal temperature is 64°F (18°C). Ideal pH is 7.4. It should be kept in ponds over 21 gallons (80 L).
Gudgeon (Gobio gobio)
Provide strong water movement and a substrate of sand with pebbles and stones. It reaches 6 inches (15 cm) in length. Ideal temperature is 64°F (18°C). Ideal pH is 7. It should be kept in ponds over 26 gallons (100 L).
Yellow Perch (Perca flavescens)
Juveniles of this attractive species tend to shoal, though adults are more solitary. Provide an abundance of tall vegetation. It has a rather long breeding season, spawning between February and July. It reaches 8 inches (20 cm) in length. Though it tolerates temperatures as high as 86°F (30°F), ideal temperature is 64°F (18°C). Ideal pH is 7.2. It should be kept in ponds over 39 gallons (150 L).
Rudd (Scardineus erythrophthalmus)
This highly active surface feeder breeds freely where there is an abundance of aquatic plants. It grows to a length of 8 inches (20 cm). While it prefers a temperature of 64°F (18°C), it tolerates temperatures up to 102°F (38°C). Ideal pH is 7. It should be kept in ponds over 52 gallons (200 L).
Amur catfish (Pelteobagrus fulvidraco)
This small (10 inches (25 cm)) insectivore is safer with pondmates than are most catfishes. It may benefit from medications that eliminate intestinal parasites. Provide plenty of shade. Ideal temperature is a relatively chilly at 54°F (12°C). Ideal pH is 7.6. It should be kept in ponds over 66 gallons (250 L).
Golden orfe (Leuciscus idus)
A lively surface feeder, this species is suitable only for larger ponds with ample open surface area. It is known to be quite hardy. Some orfe may reach 18 inches (45 cm) in length. They may spawn when water temperature rises above 50°F (10°C). Ideal temperature is 64°F (18°C). Ideal pH is 7.5. It should be kept in ponds over 105 gallons (400 L).
Sterlet sturgeon (Acipenser ruthenus)
This primitive fish reaches a length of 49 inches (125 cm). It may prey on small fish and invertebrates. Its water may be somewhat turbid but must always be kept cool and well-oxygenated. Provide a sand or gravel bottom that is mostly free of obstructions such as large sunken logs or thick weeds. It spawns over gravel beds in mid-spring to early summer, though it is unlikely to breed in the typical home pond. Ideal temperature is 64°F (18°C). Ideal pH is 7.8. It should be kept in ponds over 105 gallons (400 L).
Golden shiner (Notemigonus crysoleucas)
This fish is a highly active open water swimmer that does best in shoals; therefore, though it is moderate in size (10 inches (25 cm)), it requires a fairly large pond. Ideal temperature is 68°F (20°C). Ideal pH is 7. It should be kept in ponds over 132 gallons (500 L).
Grass carp (Ctenopharygodon idella)
This sturdy fish is highly regarded by pondkeepers for its ability to survive very cold winters, but is most famous on account of its huge appetite for aquatic vegetation. To say the least, it is not a species to keep with valuable ornamental plants; on the other hand, it may used very effectively to control the overgrowth of certain prolific plant types. It reaches 36 inches (91 cm) in length. It spawns when water temperature is between 79 and 82°F, though it is unlikely to breed in captivity. Ideal temperature is 64°F (18°C). Ideal pH is 7.5. It should be kept in ponds over 264 gallons (1,000 L).
Channel catfish (Ictalurus punctatus)
An albino form is available in the aquarium trade. Topping out at a length of 47 inches (120 cm), this larger catfish poses a threat to any fish much smaller than itself. It prefers clear, cool, well-oxygenated water. It spawns between April and July as water temperatures reach 73°F (23°C). Ideal temperature is 64°F (18°C). Ideal pH is 7.6. It should be kept in ponds over 264 gallons (1,000 L).
Shovelnose sturgeon (Scaphirhynchus platorynchus)
This species is similar in its care to the sterlet sturgeon, though it reaches the much larger size of 39 inches (99 cm). Ideal temperature is a relatively warm 73°F (23°C). Ideal pH is 7. It should be kept in ponds over 1320 gallons (5,000 L).
While koi and goldfish make for excellent pond livestock, there is a surprisingly great diversity of fishes that can potentially be stocked in ponds of virtually any type or size. Such options include species than can be used for both ornamental and utilitarian purposes. Locating sources for some of these fishes can require a considerable amount of footwork. However, as demand for these species increases, pondkeepers may soon enjoy a greatly expanded selection of fishes. Dedicated hobbyists are encouraged not only to do a little of their own research, but also to urge their favorite suppliers to include them amongst their more staple offerings.