This^^Not really. Peacing is nice, but like you said it breaks fast. Your best bet would be to paralyze it. If you're still having trouble you could take down it's hp so that the firebreath isn't a problem
For pets with the poison skill -- the skill level is completely superfluous and that the pet will poison the same regardless of their skill.You get max stats but it knocks down skills. On pets with skills max of 100, that's fine, its just less fine when its something like a Death Beetle with over-100 skills.