fish n chips,if this was my pond i would have added 1 or 2 nice lmb as soon as I saw the fish.I'd then probably have waited till temps where in rainbow territory and added them,all the while keeping a eye on things.While playing around as soon or if the rainbows start to look skinny I'd fire up a feeder and or add fat heads in order to have table fare come spring.
Depending on things that happen,come spring I'd eat well on the rainbows and have rethought my plan.and more then likely depending on the lmb I added I'd try and prevent a spawn.
but that is me and i'm far from a expert,although unlike the experts I don't believe in killing off ponds unless absolutely unavoidable.