Recovery mode doesn't work
When you are in fastboot mode you can directly start the recovery image without installing it: 

fastboot boot recovery.img


Alternatively if you want to start the installed recovery rom execute 

fastboot flash recovery recovery.img    
fastboot reboot bootloader


and then select Recovery using Vol-Up/Down buttons + Power button to start the recovery ROM.

Note that some stock firmware images will replace the recovery ROM back to the original one once you start the main OS. This is automatic "updating of the recovery ROM" is part of the boot process.