Orthrus doesn't heal 1st generation, it must be hatched into it. Starfish can be bought from the pet vendor in Celestia for 10,000 gold, it can learn Spritely and also has Spell Proof, so it's a pretty good base pet for starting out your pet talent pool.
Funny how it has grown. Back when I got my Fierce Hound with the castle bundle it was rare to even get MC Sprite, so few pets had the ability and here was a pet that got it at Teen no matter what. It was very handy for my first wizard trying to learn the game at level 40 in mid Mooshu and solo. I got a lot of mileage out of that pet, Miss Zoe it old, lol.