Ahahahha sounds like your having lots of fun in bonny scotland!
Let me know when your back, the offer will still stand! Just bring the biscuits and I'll make the tea...lol
I had the koi way before the sturgeon arrived and at first I was a bit cautious with the koi being so bloody expensive and the sturgeon looks like a bit of a predator! But I was pleasantly suprised...
When I fist got him, he was a bit shy and you'd see little of him, but after just a few weeks he was eating from my hand etc, he's so gentle and playful you'd be amazed, you can put your hand in the water and splash about and he'll come and rub himself on your hand, let you stroke him etc...
Some of my koi cost a fair few quid (hundred's) the sturgeon was 47 pounds, and he's my most prized fish by a country mile!
Planning on building a larger pond in the summer, and having no koi but a few sturgeons and some native UK fish.... tench, grass carp, trout, bream ,chubbs, perch, everything but the pikes... (I do want pikes so badly, but not much of a community fish) hehe
I wouldn't advise getting any cat fish, like you say you don't see much of them (if anything). My mate bought some sort of albino catfish, lovely looking fish and cost him a bomb, but you might see it for a few seconds in a whole day! I have some loaches that are pretty big, well they were last time I saw them (like a year ago!!!)
My next pond build I'm thinking nice and big maybe 16ft by 8ft... But very shallow 3ft maximum.... only problem with shallow is you will need to have net covering cos those damn herron's and hawks will be regular visitors (i have a cure tho, discuss on pm) lol