Fancontrol Mac, Right fan "-1 Rpm"?

[MrFluffums]

I downloaded fancontrol for mac, and I noticed the readout says that my right fan is spinning at -1 RPM? Is this an error, or can I fix this somehow?

Heres a picture.
http://cl.ly/0t1l1W2S032c0F2w0d1H

 

[crunkcrumpet]

13" MBP? If so, it's because the 13" only has one fan on the left side