7 Sturgeon Species (Facts & Pictures)

Unique in the animal world for their primitive appearance, sturgeons are fascinating creatures that have been around for millions of years. Their morphologies have remained largely the same throughout the fossil record, making them living fossils. These seemingly armored creatures belong to the ancient Acipenseridae family, which includes basal ray-finned fishes with cartilaginous exoskeletons. Modern-day sturgeon species are grouped under 4 genera: Acipenser, Huso, Scaphirhynchus, and Pseudoscaphirhynchus.

Most sturgeons are found in temperate and sub-arctic environments in Europe, Asia, and North America. As bottom-feeders, they typically spend most of their lives in nutrient-rich rivers and estuaries. To an extent, some species are anadromous. They spend most of their time in brackish waters along the coast and migrate upstream to spawn in large rivers.

Unfortunately, current environmental challenges have placed enormous pressures on these fish and their natural habitats, and they are now classified as some of the most endangered freshwater species in the world. 23 out of 27 sturgeon species are in danger of extinction, particularly due to the luxury caviar trade.

Interested in rearing fish that may outlive all fauna in your pond, and may perchance even live longer than you? Then look no further, as some sturgeons can live up to 100 years! These long-lived fish are endlessly interesting and somewhat challenging as pond pets. Due to their sheer size, they will require large pools and should the majority of the time be handled by experts. They are hardy fish and are extremely adapted to cold water conditions, but may have more special requirements compared to other pond fish. Listed below are some sturgeon species you might find interesting, along with important information to consider prior to making a purchase.

Sturgeon Species

1) Siberian sturgeon (Acipenser baerii)

Extremely valuable in the aquaculture industry, Siberian sturgeons are farmed for both meat and caviar. This species can grow to be massive, with record weights above 200 kg (440 pounds). Slow to reach reproductive maturity, they can live up to 60 years old. The slow rate of maturation has increased this species’ vulnerability to overfishing in the wild, where they are often found in congregations at the bottom of lakes. They tend to prefer depths of 20 – 50 meters (65 – 165 feet) but have been shown to reach a depth of 150 meters (492 feet). In natural lakes, this benthic feeder preys on a variety of bottom-dwelling invertebrates, such as larvae, crustaceans, and polychaetes.

In terms of their life history patterns, there are two categories of Siberian sturgeons. The first are semi-migratory and swim thousands of kilometers each year to spawn in colder, more oxygenated waters. The second (given the subspecies epithet “baicalensis”) are largely restricted to freshwater bodies inland and are found in considerably smaller populations. Siberian sturgeons are light-gray to dark-brown, with bellies that are either white or yellowish in color. At maturity, this species can reach a length of 2 meters (6.5 feet), though this is largely dependent on the river population from which they arise.

This species is only advisable for growth in large ponds, with water volumes that range from 6,000 – 15,000 gallons (22,700 – 57,000 liters). Accustomed to seasonal temperature variation, Siberian sturgeons can tolerate water temperatures between 1 – 26 ˚C (34 – 79˚F). They can also tolerate low oxygen conditions, but will generally be more resistant to diseases when provided with high O₂ levels. Siberian sturgeons are fairly peaceful and can be reared alongside large koi, but do bear in mind that they may occasionally consume smaller fish that reside close to the pond bottom.

2) Diamond sturgeon (Acipenser gueldenstaedtii)

Critically endangered in the wild, the diamond sturgeon is one of the rarest sturgeon species, yet the most commonly found in fish shops due to its eye-catching appearance. Also known as the Russian or Danube sturgeon, this species is easily distinguished by its dorsal and lateral scutes, which are white or cream-colored against a generally dark blue to black body. In comparison with other sturgeon species, the diamond sturgeon is also set apart by its rounded nose.

This large fish can grow remarkably quickly and reach a length of 2.3 meters (7.5 feet) in the wild. On average, they reach a shorter length of 1.25 m (4.1 feet) in ponds. Diamond sturgeons will typically need access to a water volume of 6,000 – 8,000 gallons (27,000 – 36,500 liters) if you intend to raise them into maturity. This rapidly growing species will require high-quality sturgeon food, without which it may suffer from malnutrition. Given proper growth conditions, a diamond sturgeon will increase in length by around 10 – 12 inches (25 – 30 cm) per year. Once it has reached a length of about 1 meter, its rate of growth will begin to slow down, making way for its body to properly fill out.

This species thrives best in cooler temperatures and will require proper filtration and aeration. Conditions that are suitable for koi are appropriate, but don’t forget that sturgeons will require more free space around the pond bottom. Plants along the bottom surface of the pond may be detrimental to this species, as they are unable to swim backward or maneuver through plants as easily as other fish. Additionally, neutral water pH and virtually zero ammonia are a must.

3) Stellate sturgeon (Acipenser stellatus)

Also referred to as the starry sturgeon, this species is similar in appearance to the diamond sturgeon and is likewise critically endangered in the wild. It has been heavily overfished in its native range, with only a few spawners remaining in the Black Sea. The caviar produced by this sturgeon is now restricted as a trade item. Unlike the previous species, the stellate sturgeon is distinguished by its long, thin nose and its 5 short barbels that are situated close to its mouth. Its body is dark-gray to black and is covered by rows of cream-colored scutes along its dorsal, lateral, and ventral regions. Considered a must-have by sturgeon collectors, A. stellatus have relatively large heads that can make up a fourth of their total body length.

Compared to the diamond sturgeon, A. stellatus can be grown in smaller ponds as they are more slender. However, they are avid swimmers that will require ample space for swimming and at least a mild current. A pond volume of at least 3,000 – 6,000 gallons (11,300 – 22,700 liters) is suitable for rearing this species into maturity. In the wild, stellate sturgeons can reach a weight of 70 kg (154 pounds) and a maximum length of 2.2 meters (7.2 feet). In captivity, this species rarely exceeds a weight of 15 kg (33 pounds) and will mature to a length of just 1.3 – 1.5 meters (4.3 – 4.9 feet).

For proper growth, stellate sturgeons will require strictly maintained oxygen levels, which must be boosted further during the summer months. In cases where oxygen levels are insufficient, sturgeons are more susceptible to a host of parasitic or bacterial diseases. They will have to be treated with proper medication that will, at times, largely differ from those used for other fish species. Additionally, high-quality sturgeon food is essential for this species to reach an acceptably long lifespan.

4) Sterlet (Acipenser ruthenus)

One of the smallest of all true sturgeon species, Acipenser ruthenus is often sold as the ‘dwarf sterlet’. This species is perhaps the best option for the more average-sized outdoor pond. It is red-listed as ‘vulnerable’, however, as its population numbers in the wild are decreasing. Unfortunately, the smallest individuals are considered a delicacy by Russian fishermen, who refer to them as “Danube’s fish sticks”. For this reason, the EU has developed a law that prohibits fishing for sterlets under 40 cm (16 inches).

The typical morphology of this species is less eye-catching compared to the diamond and stellate sturgeons, but you may be fortunate enough to find an albino specimen at your local aquarium shop! The pigmented varieties will typically have 11 – 18 dorsal scutes that are slightly paler than the rest of their dark-gray to black bodies. The sterlet reaches a maximum length of 1.2 meters (3.9 feet) in the wild, and will often grow to just 60 cm (24 inches) in captivity. Though relatively small, sterlets can take almost a decade to mature and can live up to 100 years.

Sterlets will require a pond water volume of approximately 2,000 gallons (9,000 liters), though a larger pond would still be advisable if you intend to rear this fish into adulthood.  It is considered a good species for beginner pond owners, as it may be handled without the help of an expert. Do keep in mind, however, that this species will still require well-maintained oxygen and nutrient levels despite its smaller size.

5) Beluga sturgeon (Huso huso)

If sturgeons are known as the Leviathans and Methuselahs of freshwater fish, then the beluga sturgeon certainly takes the cake. As its common name suggests, the beluga sturgeon is the largest of them all. This giant can grow to a length of 7 meters (24 feet) and weigh up to 1,500 kg (1.65 tons). That’s as heavy as a small truck! Unsurprisingly, this famed species is on the verge of extinction and has been classified as critically endangered. To combat the permanent loss of this species, private initiatives have released thousands of juvenile beluga sturgeons into the wild.

Unlike the species listed above, beluga sturgeons belong to the Huso genus. Sturgeons under this genus are differentiated from those belonging under Acipenser by their branchiostegal membranes, which are joined together and form a flap. Beluga sturgeons are known for being shy creatures despite their sheer size. They are typically blue or gray in color and have a rounded hump that extends along their backs. This formidable predator doesn’t stick to the bottoms of rivers and lakes; it actually ventures to the central depths of the water column in search of small fish.

Needless to say, this long-lived species is perhaps not the best candidate for rearing in garden ponds. A very limited number of aquaponic facilities grow these species, as permit exemptions are required. Like other sturgeons, belugas were heavily hunted in the wild for their roe, which can sell for up to US$8,000/kilo! In the US, only Sturgeon Aquafarms has been provided with the necessary exemptions to produce beluga caviar and meat. This facility highlights the importance of protecting wild populations of this species and adopts sustainable methods of fish production.

6) Shovelnose sturgeon (Scaphirhynchus platorynchus)

The smallest of the North American sturgeons, the shovelnose is a freshwater species that is commonly referred to as sand sturgeon, switchtail, or hackleback. This species is economically important as it is commercially fished out of the Mississippi and Missouri river systems. In the wild, it feeds along the bottom region of nutrient-heavy river channels by protruding its mouth and sucking up food. Typical prey types include fly larvae, worms, small fish, and crustaceans. Due to its proclivity for bottom-feeding, it serves as a host to the larvae of many mollusk species.

As depicted by its common name, this elongated fish has a flattened snout that is obtusely rounded at the tip. Adding to its character, its snout points upward and looks lightly freckled. The dorsal and lateral regions of the shovelnose are light brown in color, helping it camouflage in its natural environment. In contrast, the belly of this sturgeon is white. Its features are quite similar to those of its close relative, the pallid sturgeon (Scaphirhynchus albus), which is endangered and illegal to fish.

Shovelnose sturgeons can be reared in outdoor ponds and are often sold as aquarium fish. On average, they reach a manageable length of 50 – 85 cm (20 – 33 inches) and tend to weigh around 2.5 kg (5.5 pounds) in adulthood. This species will require pond water volumes that range from 1,000 – 2,000 gallons (4,500 – 9,000 liters). As with all the aforementioned species, the shovelnose sturgeon requires proper pond oxygenation and high-quality sturgeon feed.

7) White sturgeon (Acipenser transmontanus)

Here’s a sturgeon species that you’ll definitely want to have in a large pond! This attractive fish is commonly reared in aquaculture facilities and sold to aquarists in the US. Generally anadromous, the white sturgeon is usually found in large estuaries that exit into the Pacific. To spawn, this species travels long distances through several inland river systems. The connectivity of natural populations has largely been affected by dam construction and overharvesting, as this species also produces economically important roe and meat. It is even known for its oil and its swim bladders, which are used to produce isinglass. 

White sturgeons have cylindrical, elongated bodies that can reach lengths above 3 meters (10 feet) in the wild. Though sold as juveniles that fit perfectly in one hand, this fish is not for the faint of heart because it can grow to as much as 630 kg (1,400 pounds)! Toothless and quite gentle as a pond fish, this giant uses its vacuum-like mouth to suck protein-rich prey, such as bottom-dwelling worms, crustaceans, and mysid larvae. Its peaceful temperament has even encouraged the use of this species in petting zoos, where children can interact with the fish and learn more about its life history.

White sturgeons will require pond water volumes that are upwards of 6,000 gallons (22,700 liters) for them to reach a considerably large size. This species will thrive best in cold water but can tolerate warmer conditions of up to 26˚C (79˚F) as long as a current is provided. Proper oxygenation is also a must, with dissolved O₂ levels above 5.0mg/L at all times. Do keep in mind that if you intend to raise your sturgeon alongside other fish, they may compete with it for high-quality fish food. The best way to ensure that your sturgeon gets access to proper nutrition is by training your fish! You can try feeding your sturgeon at the same place and time every single day to get it accustomed to a feeding regimen. Who knew fish could be trained too?!