Have done TFS stocking many times into fully inhabited ponds (adult predators). Bob has a post on it and I will find you the link. My opinion - you need a good plankton bloom/base. Stock in spring - adult TFS so they will spawn soon thereafter. LMB will not eat all the millions of new TFS fry. Be ready to supplement stock a few adult TFS (non-spawned out) in late summer to early fall to ensure a solid yoy base going into winter.