Questions on pet leveling

My pet been on lvl 2 for a while have fusion 3 is there an exp bar for pets?

 

Your pet have 2/2 level.
So its max level is only 2.
If you want to fuse, you should max the pet level first.
Because the new fused pet max level is the avg of previous pet +1
For example if you fuse lvl 1 and lvl 1 the new pet max lvl = (1+1)/2 +1 = 2
If you fuse lv 150 and 126 = (150+126)/2 +1 = 139

 

So you have 2 keep burning pets to level a spefic one out?

 

No, just buy pet with high lvl potential.
And fuse it only after you maxed their lvl.
Don't fuse at lvl 1 or you'll waste their max lvl potential

 

And you need to lvl pet skills before you fuse pet, otherwise the skills you pick from fusion will not lvl up anymore.
Here is an example of finished fusion