Don't call him Aqualad!
Superman wasn't the only Justice League Member cloned! After an exhaustive study of the Justice League members, Superboy's creators realized that Aquaman was the only other member minus perhaps the Martian Manhunter that was born with powers.
Thus Aquaman was cloned and thus was born Experiment 25 also known as Aquaman II, don't call him Aqualad!
Now Superboy and Aqualad join their Young Justice fellow Members in search of the final clone the Kid Martian!