Mages who are Level 35 and under should use Mana Shield. Summons work do well when facing these; it is best to run them and use Energy Damage.
Paladins should run these, just like a Wyvern, by shooting and avoiding the wave attacks. The Exori con spell is of tremendous benefit here, so use it often. Likewise, Flash Arrows are well-suited to employ against this reptile. A level 37 Paladin with 67 Distance Fighting using a normal Bow can, for example, expect to use 13 of these energy arrows per kill, on average. As hatchlings are so stingy with their loot, and the cost of these specialized arrows so high, this is hardly economical, but it certainly makes for good Powerleveling. An alternate strategy is to come at them with Royal Spears and a very good Shield, e.g. 31 defense, and use Exori con continuously. In any event, bring lots of Health and Mana Potions, or expect a trip to the Temple.