Moonfire and Sunfire are already part of the default debuffs, though they should only show when in Moonkin form. Is this not correct?
Just to be sure the correct spellID is there, put this in chat and press enter:
Code:
/run FindSpellID("Moonfire", "target", true)
This will output the spellID for the debuff the next time it gets applied. Then do it again, but with "Sunfire" instead.