Hi Jon,
You are correct—it is anti-clockwise (lefty-loosey) to release the blade nut on a Frisky Fox.
A few tips to help:
1. Safety First: Ensure the spark plug lead is disconnected before you put your hands near the blade.
2. Leverage: Use a long-handled wrench or a "breaker bar" if you have one; the extra leverage is usually more effective than soaking it in oil.
3. Block the Blade: Wedge a thick block of wood between the blade and the mower deck to stop the blade from spinning while you apply pressure to the nut.
If it still won't budge, a quick sharp tap on the end of the wrench with a hammer can sometimes help "shock" the bolt loose.
Best regards Mark