Honestly, as a level 60 mage, I never once used the fire pet seriously ... at any level.
Water was my main pet, for anything I could kill with one pet. The earth pet was my second main, for fighting anything that requires chaining pets. And the air pet was ... all I could use in Plane of Sky, so at least it got some use there
[You must be logged in to view images. Log in or Register.]
But fire? I guess it's good if you're fighting really low level blues, but I just never needed it at any of the camps I did.