Thanks for the positive comments.
I saw him at my LFS (who aren't known for keeping fish very well!). He was labeled as a regular Sturgeon at my LFS but people have since suggested it's a diamond sturgeon.
When I got him he was about 7" and skinny as hell. Had him around four years now and he's just under 3ft (a lot of that being tail!).
I keep him with koi from 4" to about 14".
He feeds on sturgeon pellets, koi pellets, and also sometimes on bits of bread.
Cool fish always active.
I didn't realize they'd been kept warm in aquariums. I'm very surprised also cos of how big they get and how active they are. But these are very cool fish.
If it were down to me I'd have a species pond just for them.
We can all dream right