If you caught a Rainbow Trout in Lake Muskoka, it was likely an escapee from the local Trout Farm in Milford Bay if you encountered one. The dam blew out in the spring due to flooding, and some trout were lost. It has since been repaired.

Wow, how interesting! I know the trout farm you are talking about, it's on Hewlitt Rd. I have only seen one rainbow and that was caught by my Father in Scarcliff Bay, Milford Bay area. a very long time ago