Originally Posted by
K. Jones
A decent, but not unmanageable number. Keeping this pretty strict - trying to stick with people where if "Aqua" was a symbol like Batman's Bat, these would be like, "Aquawoman, Aquagirl, Aquaboy, yadda yadda". (also excluding characters from their own stories that just tend to run into Aquaman a lot because oceanic adventures, like the Sea Devils, Golden Agers like Red Torpedo or Neptune Perkins, Neptune's extended family like Tsunami and Deep Blue, and Arion, or Shiny Happy Aquazon or Senior Waveman and so on. One big exception to this, though, is Dolphin. She's officially "adopted" into the Aquaman family, I think.)
Garth (of Shayeris). "Tempest". (Formerly Aqualad). Aquaman's original Silver Age sidekick, Garth dates ... almost back into Golden Age territory.
Mera (of Xebel). So bad-ass she never needed a superhero name. Aquaman's eternal paramour and probably the second toughest chick in the DCU.
Orm Marius. "Ocean Master". Yeah, he's one of Aquaman's chief villains, but he's also his brother, so there's that going on.
Arthur Curry Junior. (AKA Aquababy). Not currently canonical that we know of, Aquaman was like the first O.G. hero to actually get married and have a baby, and A.J. was also one of the first casualties of proper supervillain EVIL, because Black Manta totally killed the kid, although he kinda/sorta/semi turned back up in lame ways over the years.
Dolphin. Originally a one-shot character not tied to Aquaman in a standalone DC tall-tale, she became a regular for obvious reasons - underwater lady.
Tula Marius. (AKA Aquagirl). Introduced in the Bronze Age and paramour of Garth, she died in Crisis but is thankfully back now in a big way. New canon, but as of I dunno, Johns' second year in the New 52, she's the half-sister of Ocean Master.
Koryak. (AKA Narwhal). Post-Crisis, a lot of DC characters were long in the tooth and had a lot of nearly grown-up "kids they didn't know about" turning up in their lives. Koryak was the son of Aquaman and an Inuit girl named Kako. Probably the weakest character on the list in addition to being the hardest to bring back into continuity in any way, since having a 16-17 year old son ages Aquaman in hard-to-fathom ways.
Lorena Marquez. "Aquagirl". San Diego girl turned into a submariner in a manufactured disaster - Sub Diego is a can't miss storyline.
Jackson Hyde. "Aqualad". (AKA Kaldur'ahm). Introduced only a few years ago, made popular by Young Justice (TV), and finally getting his development in the books.
Garth, Mera, Ocean Master, Dolphin, Tula, and Jackson are all major players in present day comics, though Garth and Jackson do most of their heavy story beats in Titans and Teen Titans, respectively. A.J. and Koryak are currently non-canon. Lorena is easily poised for a comeback, though - nothing says Sub Diego can't still be canon. Before Johns revitalized Aquaman, the Sub Diego period was probably the best Aquaman period in 20 years, and she's a fan-favorite with a great costume design.
There's also Tom Curry, his dad - deceased lighthouse keeper and probable one-time ocean explorer, and Atlanna Curry, his mother, queen of Atlantis - alive, but exiled. And Vulko is sort of like his Alfred. If Alfred was a treacherous political player who could never really be trusted.