[Ebook] Encyclopedia of Aquarium & Pond Fish – Directory of Pond Fish – Other coldwater fish

Directory of Pond Fish

Other coldwater fish

In addition to goldfish and koi, many other fish from a wide range of families thrive in coldwater ponds, from small, colorful species, such as this Red Shiner (see also p.361), to prehistoric-looking sturgeon. However, the keeping of coldwater fish has raised environmental concerns, principally that imported exotic species may escape into the wild and endanger populations of native fish. As a result, there are legal restrictions on the sale and movement of some species. Dealers should be familiar with these laws, but you can check with the US Department of Agriculture (or, in Canada, the Department of Fisheries and Oceans) for up-to-date regulations.

Orange-Throated Darter (Etheostoma caeruleum)

• ORIGINS: Southeastern Canada and eastern US, near the Great Lakes; also in Louisiana and Mississippi.
• SIZE: 3 in (8 cm).
• DIET: Small live foods and the eggs of other fish.
• WATER: Temperature 39–68°F (4–20°C); hard (100–150 mg/l) and around neutral (pH 7.0).
• TEMPERAMENT: Breeding males are territorial.

These small, bottom-dwelling fish are difficult to observe in ponds but are more visible in wellfiltered coldwater aquariums. In a pond setting, they supplement their diet by feeding on aquatic insect larvae. Male Orange-Throated Darters are more brightly colored than females. A rise in water temperature triggers breeding. The female lays several hundred eggs over the course of two or three days and buries them in mulm on the pond floor.

Three-Spined Stickleback (Gasterosteus aculeatus)

• ORIGINS: Occurs widely over much of Europe, northern Asia, and Africa. Also present in North America.
• SIZE: 5 in (12.5 cm).
• DIET: Prefers fresh and prepared live foods.
• WATER: Temperature 39–68°F (4–20°C); soft (50–100 mg/l) and neutral (pH 7.0 ).
• TEMPERAMENT: Males become territorial when breeding.

These sticklebacks show a distinct difference in coloration between the sexes during the spawning period, when male fish become red and blue. The male builds a nest out of plant matter and lures a succession of females inside so that they can lay their eggs, which he fertilizes. In total, the nest may contain as many as 50 eggs from different females. The male guards the eggs and also watches over the newly hatched fry.

Orange-Spotted Sunfish (Lepomis humilis)

• ORIGINS: North America, where it occurs in rivers and lakes from Texas to North Dakota.
• SIZE: 4 in (10 cm).
• DIET: Mainly live foods of different types.
• WATER: Temperature 39–72°F (4–22°C); hard (100–150 mg/l) and neutral (pH 7.0).
• TEMPERAMENT: Occasionally aggressive.

The small size of these sunfish, coupled with their attractive appearance, means that they can be kept in coldwater aquariums as well as in ponds. Sexing is quite straightforward, since only males display the distinctive reddish-orange spots, which are brown in females. The white edging around the so-called “ear flap” behind each eye is another point of recognition. Avoid housing them with other sunfish, because they will hybridize readily.

Diamond Sturgeon (Acipenser gueldenstaedtii)

• ORIGINS: Europe and western Asia, inhabiting the Azov, Caspian, and Black Seas; also ventures into rivers.
• SIZE: 48 in (125 cm) in ponds.
• DIET: Sturgeon pellets and live foods.
• WATER: Temperature 50–68°F (10–20°C); hard (150–200 mg/l) and neutral to alkaline (pH 7.0–7.5 ).
• TEMPERAMENT: May prey on small fish.

Young Diamond Sturgeon lose their characteristic white patterning as they mature, becoming grayer with age. House them in a large, well-oxygenated pond that is free from blanketweed, among which they can become trapped. Sturgeon are highly susceptible to chemical poisoning, so avoid using algicides, which are toxic to these primitive fish, as are some medications.

Star Sterlet (Acipenser stellatus)

• ORIGINS: Europe and western Asia, inhabiting the Azov, Caspian, and Black Seas; also ventures into rivers.
• SIZE: 60 in (150 cm).
• DIET: Pellets high in oil and protein, plus live foods.
• WATER: Temperature 50–68°F (10–20°C); hard (150–200 mg/l) and neutral to alkaline (pH 7.0–7.5 ).
• TEMPERAMENT: Peaceful.

As with other members of the sturgeon family, the Star Sterlet generally grows much smaller in ponds than in the wild. It would naturally spend much of its early life in the sea, heading up rivers to spawn in fresh water when mature. Despite this, it can be kept in an entirely freshwater environment, but it requires a large pond with a volume of at least 1,200 gallons (4,500 liters). Star Sterlets can be kept with koi.

Siberian Sturgeon (Acipenser baerii)

• ORIGINS: Rivers in Siberia, from the Kolyma to the Ob; also in some larger lakes, including Lake Baikal.
• SIZE: 78 in (200 cm).
• DIET: Pellets high in oil and protein. Carnivorous.
• WATER: Temperature 50–68°F (10–20°C); hard (150–200 mg/l) and neutral to alkaline (pH 7.0–7.5 ).
• TEMPERAMENT: Peaceful.

This fast-growing fish is gray or black on top, with white underparts. Like other sturgeons, it requires cool surroundings and highly oxygenated water. It digs with its snout for food, which in its natural habitat is mainly invertebrates. Spawning is not an annual event in the wild, but when a female does spawn, she may lay in excess of 400,000 eggs. This species does not normally breed in ponds.

Sterlet (Acipenser ruthenus)

• ORIGINS Range extends from tributaries of rivers feeding the Azov, Caspian, and Black Seas to parts of Siberia.
• SIZE 48 in (120 cm).
• DIET Pellets high in oil and protein, plus live foods.
• WATER Temperature 50–68°F (10–20°C); hard (150–200 mg/l) and neutral to alkaline (pH 7.0–7.5).
• TEMPERAMENT May prey on smaller companions.

Sterlets are the most easily accommodated members of the sturgeon family, typically growing more slowly and reaching a smaller size than their relatives. Their name derives from the star-shaped bony scutes set into the skin. Sterlets are dark in color, although juveniles have white lines along their back and sides and white borders on their pectoral fins. The smaller, so-called albino variant has a pale yellow coloration that shows up well in the clear water that these fish require. In the wild, Sterlets spawn between May and June, with some females producing more than 100,000 eggs, which hatch in about five days. However, these fish rarely breed in ponds. When buying young sturgeon, regardless of the species, avoid individuals with a slightly bent body shape. This is a sign of malnutrition, which may be hard to reverse, even though specialist sturgeon diets are now available.

Fathead Minnow (Pimephales promelas)

• ORIGINS: Found through much of North America, from Canada’s Great Slave Lake southward to Mexico.
• SIZE: 4 in (10 cm).
• DIET: Flake and pelleted foods.
• WATER: Temperature 50–77°F (10–25°C); hard (100–150 mg/l) and neutral to alkaline (pH 7.0–7.5).
• TEMPERAMENT: Active and social.

Fathead Minnows are naturally brown, but there is also a yellowish strain called the Golden Minnow. These lively shoalers are not entirely hardy, but they can be moved into an indoor aquarium if necessary to protect them from extreme cold. Sexing is easy during spring, when the males develop white spots called tubercles on their gill plates. The female lays her eggs beneath rocks or raised pots, and the male guards them until they hatch about five days later.

Southern Red-Bellied Dace (Chrosomus erythrogaster)

• ORIGINS: North America, extending from Minnesota eastward to New York State.
• SIZE: 3 1⁄2 in (9 cm).
• DIET: Flake, small pellets, and live foods.
• WATER: Temperature 50–77°F (10–25°C); hard (100–150 mg/l) and neutral (pH 7.0 ).
• TEMPERAMENT: Relatively peaceful.

The small size of these minnows means that their attractive coloration will be difficult to appreciate in a pond setting, and they probably look best in a coldwater aquarium. Good oxygenation and filtration is important, since their natural habitat is fast-flowing streams. Lowering the water temperature over winter and increasing it again in spring should trigger spawning behavior. The female scatters her eggs above the substrate.

European Bitterling (Rhodeus amarus)

• ORIGINS: Europe to the north of the Alps, although it does not naturally occur in Scandinavia or Great Britain.
• SIZE: 4 in (10 cm).
• DIET: Eats a wide variety of foodstuffs, including pellets.
• WATER: Temperature 50–70°F (10–21°C); hard (100–150 mg/l) and around neutral (pH 7.0 ).
• TEMPERAMENT: Lively and peaceful.

European Bitterling will breed successfully only if their pond houses Swan Mussels (Anodonta cygnea). The female lays her eggs inside an open mussel using her prominent egg-laying tube, or ovipositor, which measures about 11 ⁄2 in (3.75 cm) long. The male then fertilizes the eggs before the mussel closes. The fry hatch and emerge from the mussel’s siphon tube about a month later.

Tench (Tinca tinca)

• ORIGINS: Occurs naturally throughout much of Europe; absent from the far south and Scandinavia.
• SIZE: 2 ft (60 cm).
• DIET: Eats pellets, which it may take at the surface.
• WATER: Temperature 32–86°F (0–30°C); hard (100–150 mg/l) and around neutral (pH 7.0 ).
• TEMPERAMENT: Social; needs to be kept in small shoals.

Tench tend to be relatively inconspicuous, since they congregate at the bottom of the pond. They are fairly easy to keep, being unfussy about water conditions, although they dislike strong currents. Adult males are recognizable by their larger pelvic fins, but usually only young Tench are offered for sale, which makes sexing difficult. A mature female lays hundreds of thousands of eggs over the course of a year. The eggs hatch a week after being laid.

• Red-and-White Tench As in orfe, goldfish, and other carp, this coloration is the result of a natural mutation, which has been enhanced by selective breeding.
• Red Tench This variety is distinguished by vivid orange- red coloration offset against variable dark markings, typically on the head and along the back. The appearance of Red Tench can be improved by color feeding: Orange-red coloration extends on to the fins
• Green Tench This is the natural color form, although its appearance may vary depending on its background. Fish living in water with dense vegetation are a much darker green than those inhabiting sparsely planted ponds: Caudal peduncle is long and broad, as shown by this young specimen

Orfe (Leuciscus idus)

• ORIGINS Widely distributed through northern Europe, although it does not occur naturally in Norway.
• SIZE 24 in (60 cm).
• DIET Pond foods and live foods.
• WATER Temperature 32–86°F (0–30°C); hard (100–150 mg/l) and neutral to alkaline (pH 7.0–7.5).
• TEMPERAMENT Social and active by nature.

Wild Orfe display the same coloration as the domesticated strain known as the Silver Orfe. All Orfe have a narrow, streamlined body shape and need plenty of space for swimming, especially as they grow larger. Keep these fish in small groups to make them less nervous. On mild summer evenings, Orfe can often be seen patrolling just below the pond’s surface in search of gnats. At this time of year, they are especially vulnerable to low oxygen levels in the water. Including a fountain or waterfall in their pond will help to address this problem by improving the level of dissolved oxygen in the water. Orfe are easy to sex in summer, since the females swell with eggs and mature males develop white tubercles on their gill plates and along the edges of the pectoral fins. These cyprinids can breed successfully by the time they are four years old. They lay their eggs among pond plants. Hatching can take nearly three weeks.

• Silver Orfe Although this strain corresponds very closely to the wild color form, it is less commonly kept than the Golden Orfe. The life span of Orfe in pond surroundings can be in excess of 15 years.
• Golden Orfe Black speckles on the upperparts offset the orange-gold coloration, which is much richer in some individuals than others. The depth of orange coloration can be improved by color feeding.
• Blue Orfe The coloration of Blue Orfe looks attractive in isolation but is not especially conspicuous in a pond setting. Unfortunately, however, Orfe generally grow too large to be housed in a coldwater aquarium.

Red Shiner (Cyprinella lutrensis)

• ORIGINS: North America, occurring in the Midwest, the Mississippi drainage basin, and northern Mexico.
• SIZE: 3 1⁄2 in (9 cm).
• DIET: Flake, live foods, and small pellets.
• WATER: Temperature 50–77°F (10–25°C); hard (100–200 mg/l) and neutral to alkaline (pH 7.0–7.5).
• TEMPERAMENT: Active and social.)

A Red Shiner’s tank should include lots of swimming space, with planting restricted to the back and sides. The water must be well filtered and oxygenated. Reduce the temperature over winter to mimic the changes that occur in the wild. When you raise the temperature again in spring, males will become more colorful, and females will swell with eggs. Spawning then occurs in the substrate.

Rudd (Scardinius erythrophthalmus)

• ORIGINS: Widely distributed in northern Europe, but absent from much of Scotland and Scandinavia.
• SIZE: 18 in (45 cm).
• DIET: Pond pellets will be eaten readily.
• WATER: Temperature 32–93°F (0–34°C); hard (100–150 mg/l) and neutral to alkaline (pH 7.0–7.5).
• TEMPERAMENT: Social, and peaceful with other species.

These cyprinids are active shoalers that should be kept in groups. They are often seen patrolling the upper reaches of the pond. Rudd sometimes nibble aquatic plants, but they prefer to feed on invertebrates at the surface, often darting out from beneath water lilies to snatch insects. The males develop swellings on the head when entering breeding condition. Females can lay more than 100,000 eggs in batches during spring and summer. Hatching may take up to two weeks.

• Silver Rudd This is the natural color form, with a silvery sheen. Rudd can be distinguished from Roach (Ratilius ratilius) by the pelvic fins, which are located in front of the dorsal fin, rather than level with it, as in Roach: Red coloration is evident on the fins
• Gold Rudd This is a domesticated variant with a golden hue to its body. This coloration is especially evident on the head and back.

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