Oddball;941655; said:The sterlet (Acipenser ruthenus) occurs in the rivers that feed the Caspian and Black seas. They're known to travel great distances upriver but, juveniles are normally found either in the seas or in the deltas of the rivers. I haven't found any documentation on salinity levels preferred by the juveniles. But, I have to guess they'd do better in brackish conditions until surpassing a foot in length (the beginning length of individuals found upriver). And, being a [probable] brackish species while young, the pH should correspondingly be on the alkaline side to match the 2 seas they occur in.
Here's a bit of info I found:
Common Name(s): Sterlet
Scientific Name: Acipenser ruthenus
Family: Acipenseridae
Distribution: Black and Caspian seas
Temperature: 52-72° F.
Maximum Size: 48"
pH: Neutral
Diet: Carnivorous
Behavioreaceful, Solitary
Recommended Tank Size:300 Gallons
Breeding in Aquaria: Unreported
Notes: Sterlets are true Sturgeons, a primitive group of fishes characterized by their cartilaginous skeletons and rows of heavy plates along the flanks and dorsal surface. Sterlets are most unusual to see in the aquarium and attract a great deal of interest. The snout is long and the mouth is located on its underside. The fish has a tail like that of a Shark, where the backbone continues into the top lobe, which is longer than the bottom lobe.
To locate food, the Sterlet uses its four barbels, located right in front of the mouth. Because of how sensitive these barbels are, soft and sandy gravel is a must. Favorite foods include insect larvae, tubifex worms and snails. This fish is a gentle giant and will generally leave other tankmates alone. However, it should not be trusted with small, bite-sized fish.
The Sterlet is a hardy fish, and will adjust to aquarium conditions quite nicely. During the summer, the temperature may be allowed to rise to 74 degress F, but it generally should be kept between 54 and 65 degrees F. If the temperature rises higher than 70 degrees, the oxygen level will become low, and an extra source of oxygen is required. A pump or powerhead will provide this quite nicely. Good water current is essential to this fish's health, as is clean and clear water, so a powerful filtration system is a must.
Sterlets won't spawn in the home aquarium, but in nature the fish breeds in May and June and produce 11,000-135,000 eggs. Sexing information is unknown. The name Sterlet refers to the small bony stars found in the skin. These fish have a life expectancy of 25 years or more.
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There you have it.
I was close to their origin.

Keep the water under 74 degrees in Florida Yeah right. I will have to take the chiller off of my saltwater tank.