- Sterlet fish :

Sterlet (Acipenser ruthenus)

Synonyms :

Acipenser aleutensis Fitzinger, 1836 (ambiguous synonym)
Acipenser dubius Brusina, 1902 (ambiguous synonym)
Acipenser gmelini Fitzinger, 1836
Acipenser jenisensis Herzenstein, 1895 (ambiguous synonym)
Acipenser kamensis Lovetsky, 1834
Acipenser kankreni Duméril, 1870
Acipenser kostera Fitzinger, 1832
Acipenser lovetzkyi Duméril, 1870
Acipenser marsiglii Brandt, 1833
Acipenser pygmaeus Pallas, 1814
Acipenser ruthenicus Brusina, 1902 (ambiguous synonym)
Acipenser ruthensis Linnaeus, 1758 (misspelling)
Acipenser ruthenus alba Antipa, 1909
Acipenser ruthenus albinea Brusina, 1902
Acipenser ruthenus birostrata Brusina, 1902
Acipenser ruthenus brevirostris Antipa, 1909 (ambiguous synonym)
Acipenser ruthenus erytraea Antipa, 1909
Acipenser ruthenus grisescens Brandt, 1853
Acipenser ruthenus leucotica Brandt, 1853
Acipenser ruthenus obtusirostris Brusina, 1902
Acipenser ruthenus rutzskyi Johansen, 1946
Acipenser ruthenus ruzskyi Johansen, 1946 (misspelling)
Acipenser ruthenus septemcarinata Brusina, 1902
Acipenser sterlet Brusina, 1902 (ambiguous synonym)
Sterledus ruthenus sibiricus Dybowski, 1874

Sterlet (Acipenser ruthenus)

courtesy to : www.sturgeon-pond.info/blog/sterlet-acipenser-ruthenus/index.html

The sterlet (Acipenser ruthenus) is a common Eurasian species of sturgeon, one of the smaller species of sturgeon. It is a common domestic species in the UK and Europe and an angling species all over the world. It can also be grown for eating or for its caviar or isinglass.

Sterlet (Acipenser ruthenus) by Karelj

Location :

This sturgeon inhabits rivers that flow into the following seas: Caspian, Black, Azov, Baltic, White, Barents, Kara, and inhabits both the Black and Caspian seas, and ascends rivers to a greater distance from the sea than any of the other sturgeons; thus, for instance, it is not uncommon in the Danube at Vienna, but specimens have been caught as high up as Regensburg and Ulm. It is more abundant in the rivers of Russia. As early as the 18th century attempts were made to introduce this valuable fish into Sweden and the Province of Prussia, but without success.

Physical Appearance:

The sterlet may reach 16kg in weight and 100 to 125cm in length, rarely exceeding a length of 3 ft. It is quite variable in coloration, but usually has a yellowish ventral side. It is distinguishable between other European species of sturgeons by the presence of a great number of whitish lateral scrutes, fringed barbels, and an elongated and narrow snout, highly variable in length.

Feeding Habits

The sterlet’s main source of food is benthic organisms; they commonly feed on crustaceans, worms, and insect larvae.

Common Names

Albino Sterlet, Sterlet, Sterlet Sturgeon

Life Span

The sterlet commonly reaches the age of 22 to 25 years.

Sexual Maturity

Males: 3-7 years, females: 5-12 years

Fecundity

Females may lay from 15,000-44,000 eggs.

Spawning Period

Middle of April – End of May — Beginning of June.

Spawning Requirements

Sexually mature adults. Water temperature preferably 12-17°C.

As Pond Fish

Sterlets are found in aquarist stores. They prefer medium sized and large ponds, require good water conditions, and may get entangled in plants or blanketweed or other algae. They are very friendly fish; when they are older, they will happily poke their noses out of the water for you to touch. In the wild their natural food includes crustaceans and molluscs, in captivity they need specialist food such as Orchard Fisheries Sturgeon / Sterlet food pellets to ensure they get all the necessary nutrients to keep them healthy.

Sterlet (Acipenser ruthenus) by Karelj

Buy Orchard Fisheries Sturgeon / Sterlet food pellets online

Wild Sterlet habits

Wild Sterlets are thought to be even tastier than normal sterlet flesh, probably from the wide range in their diet. Wild Sterlets are opportunistic carnivores, eating shrimps, crabs, worms and small fish and sometimes supplementing it with algae when they are desperate. They often sit at the bottom of lakes and rivers gliding around in the mud for food. They also can go into caves. They also feed on newborn and young sterlets. Sterlets will rarely go for prey larger than 10 centimetres.

Taxonomy :

Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Superclass: Osteichthyes
Class: Actinopterygii
Subclass: Chondrostei
Order: Acipenseriformes
Suborder: Acipenseroidei
Family: Acipenseridae
Subfamily: Acipenserinae
Genus: Acipenser
Species: Acipenser ruthenus Linnaeus, 1758

Sterlet (Acipenser ruthenus)

courtesy to :

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.

The Sterlet (Acipenser ruthenus) (up) with white fin edges and scutical lines differs from the more uniform colour of the Siberian Sturgeon (Acipenser baerii) (Down )

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.

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.

Wild distrubution :

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.

Taxonomy :

Kingdom: Animalia

Phylum: Chordata

Subphylum: Vertebrata

Superclass: Osteichthyes

Class: Actinopterygii

Subclass: Chondrostei

Order: Acipenseriformes

Suborder: Acipenseroidei

Family: Acipenseridae

Subamily: Acipenserinae

Genus: Acipenser