Sterlet (Acipenser ruthenus): Sturgeon Web: Sturgeon Species

Sterlet (Acipenser ruthenus)

Albino Sterlet (Acipenser ruthenus)

The Sterlet (Acipenser ruthenus) is probably the slowest growing and therefore the best species for the garden pond. It 'only' grows to 1.2m in the wild but usually up to 1m in the average pond although individual specimens can vary in size, sometimes only reaching 60cm.

A good fish for the beginner. It is from the same family of sturgeon as the Stellatus, Siberian, Italian and Diamond sturgeons.

The Albino Sterlet is ideal for a pond due to the maximum size of 1m being reached only over a long period of time.

Extra oxygenation in the summer months is essential. Sterlets do not tolerate strong treatments such as formalin.

Description

Acipenser ruthenus has 11-18 dorsal scutes, 56-71 lateral scutes, 10-20 ventral scutes, 32-54 dorsal fin rays and 16-34 anal fin rays.

The snout is long and pointed with fimbriated barbels and the lower lip is split. The colour is dark brown to grey, sometimes with a dark green tint on the back, with white fin edges and belly. The scutes are paler in colour than the surrounding skin and the white scutical lines are visible running down the body.

Often sold as 'Dwarf Sterlets', they are true sturgeon; Sterlets can reach 1.2m and 16 kg in weight.

Albino Sterlets can range in colour from pure white to orange-brown. They are slower growing and a little smaller, reaching a maximum size of 1m, but otherwise share the same characteristics of the normal coloured variety.

photos showing the differences between Sterlet (Acipenser ruthenus) and Siberian Sturgeon (Acipenser baerii)

The Sterlet (Acipenser ruthenus) [left] with white fin edges and scutical lines differs from the more uniform colour of the Siberian Sturgeon (Acipenser baerii) [right]

Acipenser ruthenus is often confused with the Siberian Sturgeon (Acipenser baerii) as they are quite similar in shape. The most noticable differences are the white edges to the pectoral (front) fins and the paler scutes and white scutical lines that are clearly visible along the body of Acipenser ruthenus; the scutes and scutical lines of Acipenser baerii are the same colour as the surrounding skin and the fins do not have white edges.

Recommended Pond Size

Normal coloured Sterlet (Acipenser ruthenus)

Sterlets can be kept in ponds of 1,000 - 2,000 gallons (4,500 - 9,000 litres) for many years but bigger is better, 2,000 - 3,000 gallons (9,000 - 13,500 litres) is recommended if you want to keep the fish into adulthood.

Food & Feeding

Sturgeons DO NOT, as some people would have you believe, eat banket weed or 'clean the bottom of the pond'. Sturgeons need to be fed all year round, they need 2-3% of their body weight of good quality food per day in the summer, less in the winter.

A healthy sturgeon diet must contain a high level of animal protein, sturgeons need a minimum protein content of 40% and an oil level of 15% or more. A a small percentage of the protein can be obtained from soya but the majority needs to be from fishmeal or other animal sources.

Pellet to Sturgeon size:

2mm pellet Starter Diet Sturgeon 10-20cm (4-8in)
3mm pellet Sturgeon 20-36cm (8-14in)
4.5mm pellet - sturgeon size 30-50cm (12-20in)
6mm pellet Sturgeon 36-61cm (14-24in)
8mm pellet Sturgeon over 61cm (24in)

Stellatus (Acipenser stellatus) and Sterlets (Acipenser ruthenus) have smaller throats; use a size smaller for them.

Buy sturgeon food pellets from Orchard Fisheries »

For more information feeding your sturgeon see our Sturgeon Food and Feeding page.

Sterlets (Acipenser ruthenus)

Health Issues

The most common sturgeon health problems are food and/or oxygen related, get these two vital things right and your sturgeons should remain fit and healthy.

Use an oxygen test kit to make sure there is enough oxygen in the water. Follow the instructions that come with the kit to ensure correct results. Do not assume that there is plenty of air just because you have an air pump running. Many things can affect the amount of dissolved oxygen in the water so testing is the only way to be certain. Warm water holds less oxygen than cold water so be vigilant during hot weather, especially stormy nights when the oxygen may drop to dangerously low levels suddenly.

Feed your sturgeon plenty of the correct food all year round. For more information about feeding your sturgeon see our Sturgeon Food and Feeding page.

Avoid strong chemical treatments such as formalin/formaldehyde, Potassium permanganate, Copper sulphate or any treatment that states not to be used with Golden Orfe (Leciscus sp.) or Rudd (Scardinius reythrophathalmus), these will probably kill your sturgeon. Salt is the safest treatment to use with sturgeons. For more information about treating your sturgeon see our Medications and Treating Sturgeons page.

Provide the best possible water quaility for you fish. Run the pump and filtration all year round and keep a spare back up pump in case of main pump failure. For more information about water quality see our Water Quality page.

Albino Sterlet (Acipenser ruthenus)

Normal coloured Sterlet (Acipenser ruthenus)

Wild distrubution

Sterlet (Acipenser ruthenus) wild distrubution map

The Sterlet is is a potamodromous (freshwater only) species native to mainland eastern Europe and western Asia, inhabiting rivers draining to Black, Azov and Caspian Seas; Siberia from Ob eastward to Yenisei drainages. The main spawing grounds are in the Volga River, Ural River and the Danube River systems.

Aquaculture has resulted in intentional and accidental introductions throughout Europe but no self-sustaining populations have formed.

The Sterlet is listed as 'Vulnerable' on the IUCN Red List of Threatened Species.