Diamond Sturgeon (Russian/Goldspot) (Acipenser gueldenstaedtii)

by Terry White

Comments: Diamond sturgeons make excellent fish for the larger more extensive pond. They are very oxygen dependent and prefer over 6.5mg/ltr+ (if you have oxygen problems diamonds and Sterlets will struggle first). They are very pretty (almost cute) when young, becoming slightly drabber but very impressive when big. Shops tend to sell them as diamond Sterlets or hybrids but don't be tempted if you have a smaller (1000 gallons+) pond, go for the true Sterlet instead. A chunky fish with large shoulders and back when adult, it grows very fast (second only to the beluga sturgeon). Beware of any shop selling a diamond Sterlet as it is a fictions made-up name; the fish is a diamond sturgeon.

Due to the size they can grow they do best in a large pond of over 3000+ gallons. Maximum size in the wild is around 3m (10ft) and about 100kg (200+ lb) they can live for over 50 years, but in the home pond 1.5m (5ft) and 30kg (60-70 lb) is a very big fish, most tend to top at 1.2m (4ft) and about 10kg (22lb) but still a big fish for the average garden pond. Juvenile Diamonds tend to have the best growth at temperatures between 13-17°C, while the best growth for bigger fish is achieved at temperatures around 18-22°C.

Caution: small diamonds under 25cm (10in) can suffer from a viral infection that is almost untreatable and is fatal no mater what you do. Buy bigger fish (over 10in) that have grown out of the susceptibility to this virus that doesn't harm any other fish species apart from the white sturgeon (formally Acipenser) now Huso transmontanas.

The Diamond Sturgeon is one of most important species for caviar production and is farmed extensively to conserve and add to wild fish stocks. Artificial spawning grounds have also been created from gravel and pebbles to compensate for the loss of natural spawning grounds due to many dam and other constructions on the rivers.

Description: The Diamond Sturgeon has 8-18 dorsal scutes, 24-50 lateral scutes, 6-13 ventral scutes, 27-51 dorsal fin rays and 18-33 anal fin rays. The snout of the Diamond Sturgeon is generally short and blunt; the barbels are placed closer to the snout tip than the mouth. Although some more pointed nose specimens are available (see pic above). The female of the species tends to have a longer and stubbier nose than the male although this is not always the case. As with all sturgeon, separating male from female is impossible by eye alone. Surgical means are normally used on farms. With all sturgeon in a garden pond we can't emulate the requirements they need from a spawning ground to reproduce. The body is dark bluish to black with white/cream starry bony platelets, a slightly lighter head and a white/yellow belly. Young fish can be more distinct grey/blue/black and very pronounced white/yellow bony plates and underside.

Distribution map for Acipenser gueldenstaedtii

Wild Distribution: Found in mainland Europe and western Asia; the Black sea, the Sea of Azov, and Caspian seas and all major rivers feeding into these seas. It has also been known to migrate into the river Danube and tends to live in localised schools in the wild. An autumn migration takes place with fish over-wintering within the rivers.

As well as the standard form two variants are known. The Persian sturgeon (Acipenser gueldenstaedtii persicus) that can be found in the Southern Caspian Sea and rivers that feed into it. Another form of Persicus can be found in the Black sea and rivers of the Caucasus. Persicus tends to have a longer pointier snout that is slightly more downward pointing than the true diamond. Telling them apart by eye is almost impossible as both forms can occupy the same rivers as the true species, only a blood serum test on the proteins Albumin and Gamma globulin will reveal the true species.

Vulnerability: The Diamond Sturgeon is listed as 'Endangered' on the IUCN Red List of Threatened Species.

Bulgarian Black Sea coast near Kamen Bryag village

Biology: Males reach sexual maturity after 8-13 years and females at 10-16 years. The Diamond Sturgeon is an anadromous species, living in marine and brackish waters and only moving to fresh water for spawning. Water temperatures for spawning differ between the species 10-20°C for the standard form and 14-23°C for the Persicus strains. Spawning can be during spring, summer or autumn with different groups spawning during these times. The spawning grounds tend to be rocky, gravel, rubble or pebbly with a 1-1.5m/s water velocity at a depth of 4-25 meters. Egg production is around 11,500 per Kg of body weight and the eggs are around 2.8-3.8mm.

The eggs hatch after developing for around 100 hours at 18°C and the fry are 10-12mm in length they will feed off the egg sack for 10-12 days before starting to feed normally.

The fry will then drift downriver into brackish water unless stopped by low water levels and low flow rates, then they tend to say in freshwater until the autumn migration. The fry fall victim to many predators during its early life and suffer very high losses.

Natural Feeding: Food for Diamond sturgeon consists of mainly invertebrates; daphnia, molluscs, crustaceans, and insect larvae that it tends to dig out of the silt and gravel. Quite peaceful to other fish but will take the occasional fry and very small fish.

Orchard Fisheries Sturgeon / Sterlet Food Pellets for sale. Buy online or order by phone.

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