Pond & Lake Sturgeon Facts Guide 2020 (Lifespan, Size, Eating & Breeding)
Sturgeons belong to the family Acipenseridae and includes 27 sturgeon species that began to evolve about 250 million years ago during the Triassic Period. The species that are present today have been around for about 50 million years, remnants of the ancestral true bony fishes. Of these 27 species, only about a handful of them are considered to be suitable for ponds and are available for commercial sale – the beluga/great sturgeon, Siberian sturgeon, sterlet, stellate sturgeon, and the diamond/Russian sturgeon. There are also a variety of hybrids that may be available for purchase depending upon where you live.
Sturgeon are considered to be both prehistoric as well as primitive, because their appearance and overall physiology and morphology haven’t changed much from our earliest fossil records of them. They can be found pretty much worldwide, from cold freshwater sub-arctic rivers and lakes to warmer marine coastal waters along Europe and North America, as different species have adapted to different locations. Highly exploited for their roe, large size, and armored scales, the IUCN Red List of Threatened Species considers the sturgeon family to currently be perhaps the most critically endangered family, with 4 species already potentially extinct and the others threatened or endangered.
Sturgeon Dietary Needs and Feeding Behaviour
Tending to live deep in water where very little light is able to reach, sturgeon are considered to be carnivorous benthic feeders, meaning that they prefer feeding on things found at the bottom of water bodies. In nature, this includes crustaceans, shells and shellfish (like clams, shrimp, and mussels), other fish, micro and macro invertebrates, insect larvae, crabs, and barnacles.
Their bodies lack the enzymes to break down plant matter, so though they may eat wheat or soy based things that are fed to them, they won’t be able to digest them and will become thin, malnourished, and ill all the same. A high protein diet is crucial! They usually need to eat around 2 to 3% of their body weight each day, especially if they’re still growing. They’re also quite slow creatures with poor eyesight (due to evolving to live in deep, dim waters), so you’ll need to feed your other fish first, else they’ll gobble up the sturgeon food before it has a chance to sink to the bottom for the sturgeon to find using their facial barbels.
The Video below shows typical browsing behaviour of sturgeon in a pond environment with other fish, such as koi:
Lifespan, Size, & Growth Rates of Sturgeon
Very long-lived creatures, it’s not unheard of for sturgeons to live well over 100 years, though the average life span is closer to 55 due to severe overfishing and habitat degradation. These long lifespans and slow growth rates are part of the reason why they’re so threatened – they don’t reproduce quickly or often, and so it’s very hard for them to bounce back from things such as overfishing, pollution, poaching, and habitat loss.
Actual growth rate varies considerably from species to species and also depends on water quality, diet, feeding rate, and temperature. These factors also predictably influence lifespan as well. As mentioned above, it’s been found that feeding sturgeon the equivalent of 2-3% of their bodyweight each day is the best feeding rate for optimum growth and maturation. In addition, temperatures below 14° Celsius slow down growth rates in many species of sturgeon. A diet of at least 40% protein and 15% lipids is best for healthy growth.
Which Are The Smallest & Largest Sturgeons?
Among species available for use in ponds, sterlets are the smallest, growing to an average of 1 meter at a slow rate, taking about a decade to reach their adult size. Siberian sturgeons grow to about 1.5 meters and attain this much more quickly than sterlets, packing on an average of 10 inches per year. Beluga sturgeon, the largest available sturgeon species, can reportedly reach up to 10 meters and 4,500 pounds in size, though around 5 to 7 meters and 2,500 pounds seems to be more normal. Again depending on various factors, belugas can grow about a meter every 2-10 years. The largest reported beluga sturgeon was 7.2 meters long and 3,463 pounds.
Is My Pond Big Enough For Sturgeon?
Due to their substantial size, sturgeons require large ponds. For sterlets, the smallest sturgeon species, you’ll need about 1,000 to 2,000 gallons at least (per sturgeon). All other available sturgeons species should be kept in a minimum of 3,000 gallons (again, per sturgeon), and if you’d like to have a beluga don’t even think about it unless your pond is at least 15,000 gallons. Your pond should be a minimum of 4 feet deep for any sturgeon, though 10 to 15 feet is best as they prefer deep waters.
In addition, sturgeons are most active at dawn and dusk and prefer to have little to low light. In fact, they’ve evolved several unique adaptations to help them thrive in deep, dark waters – rather than using eyesight, sturgeon feel around using four incredibly sensitive, long barbels on their face. They also have electroreceptor organs, called ampullae of Lorenzini, that sense even the slightest electrical currents in the water and enable them to home in on food as well as avoid danger. To help keep your sturgeon comfortable during the brightness and warmth of day, include hiding places in your pond such as submerged logs and overhangs, and plant some shade trees along the water’s edge.
Common Sturgeon Diseases & Pond Problems
1) Sturgeon Grow Very Large
As discussed above, sturgeon grow to be quite large. One of the most common issues is pond owners not having a large enough pond for their sturgeon and so they outgrow the pond, or simply not anticipating just how large this fish family gets. Sturgeon are very difficult to re-home, and 85% of species are considered threatened or endangered, so it’s exceptionally important that you’re absolutely sure that you want a sturgeon and are prepared to give it what it needs. Also related to their size, sturgeon eat…a lot. Be certain that you are able to financially afford to feed and house sturgeon!
2) Sturgeon Will Eat Fry & Small Fish
Another occasional issue is that they may eat other fish, though this isn’t common and they usually get along just fine with all but the smallest (and/or slowest) fish species. Smaller sturgeons, like sterlets, might eat small goldfish or guppies, while larger species (like belugas) have been known to eat koi. To prevent this, make sure that you’re feeding your sturgeon regularly and at the recommended amount of about 2% of their bodyweight each day with at least 40% protein content. If you notice your sturgeon coming to the surface or bending in half, they’re not receiving enough nutrition and need to be fed immediately. Another solution is to keep sturgeon in a separate pond from your other fish.
In most cases, however, keeping smaller sturgeon species with adult koi and goldfish is perfectly fine, so long as the sturgeon do not go hungry!
3) Sturgeon Prefer High Dissolved Oxygen
Sturgeons require more dissolved oxygen than most other fish species, as in the wild they are found in the colder water at the bottom that holds more oxygen than warmer surface waters where other fish prefer to hang out and sturgeons’ large bodies use up oxygen more quickly in general. In fact, while most fish are able to survive at oxygen levels of 6 parts per million (ppm), sturgeons often suffocate and die; oxygen levels of 8ppm or above are best for them.
The usual tip of incorporating plenty of plants to provide more oxygen doesn’t really work here, as sturgeon have been known to get tangled in them (remember, they’re very large with poor eyesight and slow maneuverability). Instead, utilize a pump or aerator, and in the summer you may need to use two of them as warmer water is able to hold less oxygen and the sensitive sturgeons are more likely to die in ponds during the summer.
4) Sturgeon Can Get Parasites
While not known to be particularly susceptible to disease or illnesses (thanks, hundreds of millions of years of evolution!), they can have some trouble with parasites. The most common parasites to plague sturgeon are those, such as flukes, that attach themselves to the softer, less armored portions of the fish like around the fins and mouth and then suck the blood, potentially passing on bacteria and promoting infection in the process. To get rid of or prevent these parasites from establishing themselves, many pond owners turn to parasiticides. However, the following treatments should be avoided as they have been known to kill or seriously endanger the health of sturgeons: anything with copper or zinc (including copper sulphate), organophosphates, Formalin, and potassium permanganate.
In general, anything that is known to be harmful to golden orfes should not be used with sturgeons, either. Instead, a salt bath is recommended to rid sturgeon of any parasites. For bacteria and fungus, natural malachite green can be used, though be sure to research the dosage as high concentrations can be potentially harmful or lethal.
Sturgeon Breeding Facts & Considerations
Breeding sturgeon can take some time and patience, as they are slow creatures in all regards and may only breed once or twice per decade. Depending on the species, sexual maturity for females is reached somewhere around 15 years (but can take longer), and around 8 to 10 years for males.
A rocky pond substrate of gravel or stones is needed, as in the wild this is what they would seek out to lay their eggs in. In addition, your pond will need to be several meters (at least 3) deep, with a fair amount of movement (sturgeon in the wild tend to reproduce in rivers), and relatively cool water (this depends on the species, but below 70°F is best).
Sturgeon are broadcast spawners, meaning that the females lay their eggs and allow fast flowing water to carry them until the eggs’ sticky surfaces attach to rocks and gravel, then the males spray sperm, which is also carried by fast flowing water to the eggs. This is why sturgeons (with the exception of lake sturgeons) tend to have a greater chance of spawning in waters with turbidity and flow.