Taking a crab trick-or-treating isn’t a wise idea — it might pinch at the bowls of candy or suddenly scurry out of sight — and asking an otter to help you hang Halloween decorations is a no-go, seeing as how the animal would likely want to frolic rather than put up lights.

But we can commune with the critters of the sea at our local aquariums in a fall-fun fashion, thanks to the seasonal celebrations staged by some of the ocean institutions of our ocean-close region.

The Aquarium of the Pacific will host a Scarium Family Night Oct. 17, giving revelers a chance to dress up and trick-or-treat at the Long Beach destination.

A scavenger hunt is part of the evening scene, too, as well as a magician (the performer, it should be noted, is a vampire).

There’s no need to wear your best shark attire or rock your rock lobster look, but if you do have an aquatic costume that will make a few waves, you may make a splash if you choose to wear it.

And Oct. 18 will find a Sea Scare haunting Cabrillo Marine Aquarium in San Pedro.

A “Siren’s Curse” has befallen the bash, which includes carnival games, Trunk or Treat, and opportunities to seek out mysterious clues around the aquarium.

Food trucks and a costume contest add to the convivial… spirit.

For details on tickets and attending, and more about what the siren may have in story, paddle by the aquarium site soon.