I'm laughing because I can see my kids doing that! So not funny when it's your kid, but I'm appreciating the fact it's not me!
I'm not sure you need to take it to the program director, as much as directly address this with your child. (However, I'm not sure that telling a bully you're a "free fish" will stop the bullying, and might even increase the bullying!) First, at a separate time when you're not disciplining, talk to your child about the difference between parenting and bullying, and that using anti-bullying tactics against parenting is not appropriate and will not be tolerated. Then discuss what the consequences will be.
When your child does this again, start implementing consequences.
N: I'm a free fish...
You: Ok, free fish, you just lost privilege X, and if you continue to take no notice of me, you will also earn chore X (or whatever your consequences are). You have to the count of 3 to start your bath or brush your teeth.
N: (hopefully will start to take notice of you, but if not...) No, you can't bully me!
You: We discussed this. What is my job? (to parent) What is your job? (to listen and follow directions) Do you need further consequences? You have to the count of 3 to start your bath or brush your teeth.
Then make sure you follow through on the consequences. Good luck!