An Uncommon Find

Ok there seems to be a misconception here. The 'Rare' or 'Uncommon' doesn't apply to the scarcity of the pet, it applies to the quality if the pet. Each pet found in the wild may have exceptional scores,(hit points, speed, etc) or low scores. I just fought two [npc=45439]'s, the first was Uncommon, the second was rare.

This achievement seems bugged. As a pandaren monk the achievement does not pop up, even after catching several uncommon pets, not even after relogging, or summoning the pet.

EDIT: after a few relogging, it finally gave credit

I got it for capturing a water snake in Durotar