Big Burk my uncle use to have rainbow trout in his dugout. They never got very big, 1 lb or so but were fun to angle for with there high flying jumps.
I caught them on the smallest Len Thompson spoons in 5 of diamonds, red and white and green.
Small spinners like Panther Martin and the tiny mepps spinners worked too.
They also grabbed a worm below a bobber.
I have heard of them being caught on the multi colored miniature marshmellows, never tried them yet.
On occation they went for tiny{ 1 inch white} curly tail grubs.
I would guess that the trout you saw were also rainbows.
I have never seen any other species sold for private stockings.
Rainbows seem to be the most hardy for Sask. dugouts, more heat tolerent etc.
Good luck with the trout.
WW