They’re adorable! And you could watch them chase down, capture, and bloodily devour guppies!
But they’re also delicate and demanding, and I sure wouldn’t rush to try…and I’m an experienced aquarist. But if you really must, here’s a discussion of a standard protocol.
<3
I’ve lived most of my life far from any bodies of salt water, and the wondrous creatures that live in it. The only cephalopods I have ever seen in person come out of our local bedrock. My local ones are very early, and none are very large. Someday I will get a photo of a friends collection. He travels to cretaceous bedrock in SD and Iowa, and his entire 900 sq ft basement floor is covered with giant ammonites, and longicones, and other bizarre intermediate forms.