THC Hydra Not Working for Me

I can't get thc hydra to work for me. I am trying to brute force a website (with permission) for testing and education purposes. But the way that the Post is sent to the server is so {'username':'exampleUserName','password':'ExamplePass'}. Here is my hydra command:

hydra -l userNameHere -p passwordHere www . examplesite . com http-post-form "/:{'username':'^USER^','password':'^PASS^'}"

The colons in the POST make hydra think that it is going on to the next parameter, so I get a "You must have at least ^USER^ or ^PASS^" message. I thank you all in advance for your help.