Amazing pet battle macro to determine the rarity before you decide to actually go through with the fight.
/run for i=1,C_PetBattles.GetNumPets(2) do SELECTED_CHAT_FRAME:AddMessage(C_PetBattles.GetName(2,i).." - ".._G["BATTLE_PET_BREED_QUALITY"..C_PetBattles.GetBreedQuality(2,i)]) end
Thanks go to the WoW Pet Battle Forums. http://us.battle.net/wow/en/forum/topic/6713581954
Queue up for the fight, press the hotkey you have it assigned to and it tells you what rarity the ones you're fighting are. It's great for going back to lower zones to get rares.