Sterlet
Acipenser ruthenus
Also known asSterlet sturgeon
Water parameters
Minimum tank: 2500 L per individual at harvest size.
Feed and growth
- Feed protein
- 45% target
- Daily feed (warm)
- 1.00% of body weight
- Daily feed (cool)
- 0.50% of body weight
- Max density
- 35 g per litre
A 6000 g adult eats about 60.0 g of feed per day at optimum. 10 fish at adult size: ~600 g daily.
Legality
Rules vary by jurisdiction and change over time. Verify with your local fisheries or wildlife authority before stocking.
| Jurisdiction | Status | Notes |
|---|---|---|
| Worldwide | restricted | CITES Appendix II; international trade requires permits verified 2026-05-13 |
| California | prohibited | verified 2026-05-13 |
| European Union (bloc) | permit required | Aquaculture established in Hungary, Italy, Germany; permits via CITES authority verified 2026-05-13 |
Unlisted jurisdictions default to "check local regulations".
Origin and habitat
Native to the rivers of the Black, Azov and Caspian sea basins and to Siberia from the Ob east to the Yenisei, with introduced stocks in some Baltic and northern drainages. It is the smallest of the commonly farmed sturgeons, reaching about 1.25 m and 16 kg at most, well below Russian sturgeon or beluga, and it is one of the few sturgeons that lives entirely in fresh water rather than running to sea. It also matures early for a sturgeon: males at three to five years, females at roughly four to seven, against a decade or more in the larger species, and a female may carry 15,000 to 44,000 eggs. Sterlet caviar is a mid-range premium product. Wild numbers have fallen sharply under damming and overfishing, and the IUCN now lists the species as Endangered. The sterlet is also the sturgeon most often kept in European garden ponds.
Climate and outdoor ponds
- Climate
- cold-water (cool water required, dies in heat)
- USDA zones
- 3–8 (winter low around -40°C or warmer)
- Heating needed
- no
- Cooling needed
- yes, if summer water exceeds upper tolerance
Care notes
The most practical sturgeon for smaller-scale aquaponics, given its modest size and early maturity. It is a cold-water fish, best around 14–18°C within a tolerance of about 4–22°C, and it is notably oxygen-hungry, using a fifth to a third more oxygen than the bester hybrid or beluga, so dissolved oxygen needs to stay above about 6 mg/L. Growth is moderate on sturgeon pellet of 42 to 48 percent protein, reaching maybe 1–2 kg in three to four years, with feed conversion near 1.3 to 1.8. Harvest at 0.5–1 kg in two to three years works for meat, while caviar females need four to seven years, a shorter wait than Russian sturgeon. The bester, a beluga-by-sterlet hybrid, is also farmed and pairs sterlet's manageable size with faster beluga growth. Sterlet feed on the bottom through a protrusible, ventral mouth and need sinking pellet, never surface food. Their skin is soft and scaleless, so tanks should avoid sharp edges. Fingerlings come from sturgeon farms in Germany, Austria, Hungary and elsewhere in Europe, and from some US operations, with CITES rules covering cross-border trade. For a European grower wanting a cold-water fish with caviar potential on a shorter timeline, sterlet is the best fit.