There's two Aqualads. The original one, Garth (who started as Aqualad, changed his codename to Tempest, and currently just goes by his real name), and the new one, Kaldur'ahm.

If you watch the old 1960s Aquaman or Teen Titan cartoons, that's Garth as Aqualad. If you watch Young Justice, that's Kaldur'ahm as Aqualad.