No, it's actually a plot point (sorta) that he's the only one who doesn't have a pet (or pet equivalent, see Ch'p). At the end of the story, he's trying to get the Terrific Whatsit to fill the position. And Topo the Octopus is Aquaman's original pet, as far as I know. He's cool! Aquaman trained him to fire eight arrows from eight bows at the exact same time!